Åëëçíéêü Database-SQL-RDBMS HOW-TO ãéá Linux (PostgreSQL
-ÁíôéêåéìåíïóôñáöÝò Ó÷åóéáêü Óýóôçìá ÂÜóçò ÄåäïìÝíùí)
Al Dev (Alavoor Vasudevan) alavoor@yahoo.com
v11.0, 8 Éáíïõáñßïõ 1999
Áõôü ôï êåßìåíï åßíáé Ýíáò "ðñáêôéêüò ïäçãüò" ãéá íá åãêáôáóôÞóåôå
ãñÞãïñá ôçí SQL Database engine êáé ôá front end åñãáëåßá ôçò óå Ýíá
óýóôçìá Unix. ÌéëÜ åðßóçò ãéá ôç ÄéåèíÞ ãëþóóá Ðñïôýðùí (International
Standard language) ANSI/ISO SQL êáé åîåôÜæåé ôá ðëåïíåêôÞìáôá ôçò SQL
database engine ðïõ Ý÷åé áíáðôõ÷èåß áðü ôï world-wide internet êÜôù
áðü Ýíá "áíïéêôü ðåñéâÜëëïí áíÜðôõîçò". Ðñüêåéôáé ãéá ôï ÐÙÓ (HOW-TO)
íá åãêáôáóôÞóåôå ôçí ÁíôéêåéìåíïóôñáöÞ Ó÷åóéáêÞ SQL ÂÜóç åðüìåíçò
ãåíéÜò "PostgreSQL" óå Ýíá óýóôçìá Unix ôï ïðïßï ìðïñåß íá
÷ñçóéìïðïéçèåß óáí Application Database Server Þ óáí Web Database
Server. Ç PostgreSQL õëïðïéåß Ýíá õðïóýíïëï ôïõ Äéåèíïýò Ðñïôýðïõ ISO
êáé ANSI SQL 1998,92,89. Áõôü ôï êåßìåíï äßíåé åðßóçò ðëçñïöïñßåò ãéá
ôá ðñïãñÜììáôá äéáóýíäåóçò ìå ôç âÜóç üðùò ôá Front End GUIs, ãéá
åñãáëåßá RAD (Rapid Application Development), ãéá interfaces ãëùóóþí
ðñïãñáììáôéóìïý "C", "C++", Java, Perl, ODBC, JDBC ïäçãïýò êáé
åñãáëåßá óýíäåóçò ôçò âÜóçò ìå Web êáé ðñïãñÜììáôá ãñáöéêÞò
äéáóýíäåóçò. Ïé ðëçñïöïñßåò ðïõ äßíïíôáé åäþ éó÷ýïõí ãéá üëåò ôéò
ðëáôöüñìåò Unix êáé ãéá Üëëåò âÜóåéò åðßóçò êáé èá åßíáé ðïëý ÷ñÞóéìåò
óå Üôïìá íÝá óôï ÷þñï ôùí ÂÜóåùí, ôçò ãëþóóáò SQL êáé ôçò PostgreSQL.
Áõôü ôï êåßìåíï Ý÷åé åðßóçò ïäçãü åêìÜèçóçò ôçò SQL, êáé ç óýíôáîç SQL
èá öáíåß ðïëý ÷ñÞóéìç óôïõò áñ÷Üñéïõò. Ïé Ýìðåéñïé èá âñïõí ÷ñÞóéìï
áõôü ôï êåßìåíï óáí ðñü÷åéñï ïäçãü áíáöïñÜò. Ãéá ôïõò öïéôçôÝò, ïé
ðëçñïöïñßåò ðïõ äßíïíôáé åäþ èá ôïõò êÜíåé éêáíïýò íá ðÜñïõí ôïí
ðçãáßï êþäéêá áðü ôç ó÷åóéáêÞ âÜóç äåäïìÝíùí PostgreSQL, áð' üðïõ
ìðïñïýí íá ìÜèïõí ðþò ãñÜöåôáé ìßá ó÷åóéáêÞ SQL âÜóç äåäïìÝíùí.
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Table of Contents
1. ÅéóáãùãÞ
2. ¶ëëåò ÌïñöÝò áõôïý ôïõ êåéìÝíïõ
3. Ïé íüìïé ôçò ÖõóéêÞò åöáñìüæïíôáé óôï ëïãéóìéêü!
4. Ôé åßíáé ç PostgreSQL ;
5. Ðïý ìðïñþ íá ôç âñù ;
6. Ç PostgreSQL õðïóôçñßæåé åîáéñåôéêÜ ìåãÜëåò âÜóåéò, ìåãáëýôåñåò áðü 200 Gig
7. Ðþò ìðïñþ íá åìðéóôåõèþ ôçí PostgreSQL ; Ôï ðáêÝôï Regression ãéá ôåóô áíáðôýóóåé ôï áßóèçìá åìðéóôïóýíçò óôïí ðåëÜôç
8. Ãñáöéêü ðñüãñáììá åðéêïéíùíßáò (GUI FrontEnd Tool) ìå ôçí PostgreSQL
9. Åñãáëåßá åíüò ÏëïêëçñùìÝíïõ ÓõóôÞìáôïò ÁíÜðôõîçò ãéá PostgreSQL (GUI IDE)
10. Ïäçãïß Äéáóýíäåóçò ìå ôçí PostgreSQL
10.1 ODBC Drivers ãéá ôçí PostgreSQL
10.2 UDBC Drivers ãéá ôçí PostgreSQL
10.3 JDBC Drivers ãéá ôçí PostgreSQL
10.4 Java ãéá PostgreSQL
11. Perl Database Interface (DBI) Driver ãéá PostgreSQL
11.1 Äéáóýíäåóç Perl 5 ìå PostgreSQL
11.2 Perl Database Interface DBI
11.2.1 ÔÉ ÅÉÍÁÉ ÔÏ DBI ;
11.2.2 Ïäçãüò DBI ãéá ôçí PostgreSQL - DBD-Pg-0.89
11.2.3 Ôå÷íéêÞ õðïóôÞñéîç ãéá ôï DBI
11.2.4 Ôé åßíáé ôá DBI, DBperl, Oraperl êáé *perl;
11.2.5 ÐñïäéáãñáöÝò DBI
11.2.6 ÐñïâëÞìáôá Ìåôáãëþôôéóçò Þ áëëéþò "Êüðçêå óôéò ÅîåôÜóåéò!"
11.2.7 Õðïóôçñßæåôáé ôï DBI êÜôù áðü ðëáôöüñìåò Windows 95 / NT ;
11.2.8 Ôé åßíáé ôï DBM; Êáé ãéáôß èá ðñÝðåé íá ÷ñçóéìïðïéþ ôï DBI óôç èÝóç ôïõ;
11.2.9 Õðïóôçñßæåôáé < ôï ôÜäå ÷áñáêôçñéóôéêü > óôï DBI;
11.2.10 ×ñçóéìåýåé êáèüëïõ ôï DBI ãéá ðñïãñáììáôéóìü óå CGI;
11.2.11 Ðþò ðåôõ÷áßíù ôá÷ýôåñïõò ÷ñüíïõò óýíäåóçò ìå DBD Oracle êáé CGI;
11.2.12 Ðþò åðéôõã÷Üíù ìüíéìåò (persistent) óõíäÝóåéò ìåôáîý DBI êáé CGI
11.2.13 ``¼ôáí ôñÝ÷ù Ýíá perl script áðü ôçí ãñáììÞ åíôïëÞò, äïõëåýåé, áëëÜ üôáí ôï ôñÝ÷ù áðü ôïí httpd, áðïôõã÷Üíåé!'' Ãéáôß;
11.2.14 Ìðïñþ íá êÜíù multi-threading ìå ôï DBI;
11.2.15 Ðþò ìðïñþ íá êáëÝóù stored procedures ìå ôï DBI;
11.2.16 Ðþò ìðïñþ íá ðÜñù ôéò ôéìÝò ðïõ åðéóôñÝöïíôáé áðü ôéò stored procedures ìå ôï DBI;
11.2.17 Ðþò ìðïñþ íá äçìéïõñãÞóù Þ íá êáôáóôñÝøù ìéá âÜóç äåäïìÝíùí ìå ôï DBI;
11.2.18 Ðþò äéá÷åéñßæåôáé ôï DBI ôéò ôéìÝò NULL ;
11.2.19 Ôé åßíáé áõôÝò ïé ìÝèïäïé func (func methods);
11.2.20 ÅìðïñéêÞ ÕðïóôÞñéîç êáé Åêðáßäåõóç
12. Åñãáëåßá Äéá÷åßñéóçò ôçò PostgreSQL
12.1 PGACCESS - ¸íá ãñáöéêü åñãáëåßï ãéá ôç äéá÷åßñéóç ôçò PostgreSQL
12.2 Windows Interactive Query Tool ãéá PostgreSQL (WISQL Þ MPSQL)
12.3 Interactive Query Tool(ISQL) ãéá ôçí PostgreSQL - ÏíïìÜæåôáé PSQL
12.4 MPMGR - Åñãáëåßï Äéá÷åßñéóçò ÂÜóåùí ãéá PostgresSQL
13. Ñõèìßæïíôáò ðïëëáðëÜ êïõôéÜ PostgreSQL óå ìéá ïèüíç
14. ÅöáñìïãÝò êáé Åñãáëåßá ãéá ôçí PostgreSQL
14.1 Ãëþóóá 4çò ãåíéÜò (4GL) PostgreSQL ãéá åöáñìïãÝò ìå web êáé âÜóç äåäïìÝíùí - Ðëáôöüñìá áíÜðôõîçò AppGEN
14.2 WWW Web interface ãéá PostgresSQL - DBENGINE
14.3 Apache Webserver Module ãéá PostgreSQL - NeoSoft NeoWebScript
14.4 Ïé HEITML åðåêôÜóåéò ôçò HTML óôïí server êáé ìéá ãëþóóá 4çò ãåíéÜò ãéá ôçí PostgreSQL
14.5 America On-line AOL Web server ãéá PostgreSQL
14.6 Problem/Project Tracking System Application Tool ãéá PostgreSQL
14.7 ÌåôáôñïðÞ áñ÷åßùí dbase dbf óå PostgreSQL
15. Åñãáëåßï ãéá Ó÷åäéáóìü/Õëïðïßçóç Web ÂÜóåùí ÄåäïìÝíùí ãéá ôçí PostgreSQL - EARP
15.1 Ôé åßíáé ôï EARP ;
15.2 Õëïðïßçóç
15.3 Ôé ÷ñåéÜæåóôå ãéá íá ôñÝîåôå ôï EARP
15.4 Ðþò äïõëåýåé ;
15.5 Ðïý èá ôï âñù ;
16. PHP Hypertext Preprocessor, ìéá scripting ãëþóóá ãéá ôçí PostgreSQL ç ïðïßá åíóùìáôþíåôáé óå html êáé åêôåëåßôáé óôï Server
16.1 Êýñéá ÷áñáêôçñéóôéêÜ
16.2 Áíáãíþñéóç/Åõ÷áñéóôßåò
16.3 PHP 3 - Óýíôïìï Éóôïñéêü
16.4 Ôé ìðïñþ íá êÜíù, ëïéðüí, ìå ôï PHP/FI ;
16.5 ¸íá áðëü ðáñÜäåéãìá
16.6 CGI Redirection
16.6.1 Óçìåéþóåéò ãéá ôïí Apache 1.0.x
16.6.2 Netscape HTTPD
16.6.3 NCSA HTTPD
16.7 ÔñÝ÷ïíôáò ôï PHP/FI áðü ôç ãñáììÞ åíôïëþí
17. Äéáóýíäåóç ìå PostgreSQL ìÝóù Python
17.1 Ðïý ìðïñþ íá âñù ôï PyGres ;
17.2 Ðëçñïöïñßåò êáé õðïóôÞñéîç
18. Åðéêïéíùíßá ìåôáîý PostgreSQL êáé WWW - WDB-P95
18.1 Ó÷åôéêÜ ìå ôï wdb-p95
18.2 Åßíáé áðáñáßôçôï ï äéáêïìéóôÞò ôçò PostgreSQL, ôï pgperl, êáé ôï httpd íá åßíáé óôïí ßäéï host;
19. ÐñïãñáììáôéóôéêÝò äéáóõíäÝóåéò ãéá "C", "C++", ESQL/C êáé Äõáäéêïß ÔåëåóôÝò ãéá ôçí PostgreSQL
19.1 Äéáóýíäåóç ãëþóóáò "C" ìå ôçí PostgreSQL
19.2 Interface ãëþóóáò "C++" ãéá ôçí PostgreSQL
19.3 ESQL/C ãéá PostgreSQL
19.4 Äõáäéêïß ÔåëåóôÝò ãéá ôçí PostgreSQL
20. Japanese Kanji Êþäéêáò ãéá ôçí PostgreSQL
21. ÌåôáöïñÜ ôçò PostgreSQL óå Windows 95/Windows NT
22. Ëßóôåò áëëçëïãñáößáò
22.1 ÁðïêôÞóôå Ýíá äùñåÜí ëïãáñéáóìü e-mail
22.2 ÁããëéêÞ Ëßóôá Áëëçëïãñáößáò
22.3 Áñ÷åßï ôçò Ëßóôáò Áëëçëïãñáößáò
22.4 ÉóðáíéêÞ Ëßóôá Áëëçëïãñáößáò
23. Ôåêìçñßùóç êáé Âéâëéïãñáößá
23.1 Ïäçãïß åêìÜèçóçò êáé Åã÷åéñßäéá
23.2 Online Ôåêìçñßùóç
23.3 ×ñÞóéìç Âéâëéïãñáößá ÁíáöïñÜò
23.4 Êåßìåíá ðñïäéáãñáöþí ANSI/ISO SQL - SQL 1992, SQL 1998
23.5 Óýíôáîç ANSI/ISO SQL 1992
23.6 Óýíôáîç ANSI/ISO SQL 1998
23.7 Ïäçãüò åêìÜèçóçò SQL ãéá áñ÷Üñéïõò
23.8 ÐñïóùñéíÞ åðÝêôáóç (extension) óôï SQL92
23.9 ÔìÞìá 0 - Áðïêôþíôáò ôá êåßìåíá ISO/ANSI SQL
23.10 ÔìÞìá 1 - ÔñÝ÷ïõóá êáôÜóôáóç ôïõ ISO/ANSI SQL
23.11 ÔìÞìá 2 - ISO/ANSI SQL Foundation
23.12 ÔìÞìá 3 - ISO/ANSI SQL Call Level Interface
23.13 ÔìÞìá 4 - ISO/ANSI SQL Persistent Stored Modules
23.14 ÔìÞìá 5 - ÔõðïðïéÞóåéò - Äåóìåýóåéò ISO/ANSI SQL/ ISO/ANSI SQL/Bindings
23.15 ÔìÞìá 6 - ISO/ANSI SQL XA Interface Specialization (SQL/XA)
23.16 Part 7 - ISO/ANSI SQL Temporal
23.16.1 ÅÉÓÁÃÙÃÇ
23.16.2 ÌÉÁ ÌÅËÅÔÇ- ÁÐÏÈÇÊÅÕÓÇ ÓÕÃ×ÑÏÍÙÍ/ÔÑÅ×ÏÕÓÙÍ ÐËÇÑÏÖÏÑÉÙÍ
23.16.3 ÌÅËÅÔÇ - ÁÐÏÈÇÊÅÕÓÇ ÉÓÔÏÑÉÊÙÍ ÐËÇÑÏÖÏÑÉÙÍ
23.16.4 ÌÅËÅÔÇ - ÐÑÏÂÏËÇ (PROJECTION)
23.16.5 ÌÅËÅÔÇ - ÓÕÓ×ÅÔÉÓÌÏÓ (JOIN)
23.16.6 ÌÅËÅÔÇ - ÁÈÑÏÉÓÔÉÊÏÉ ÔÅËÅÓÔÅÓ (AGGREGATES)
23.16.7 ÐÅÑÉËÇØÇ
23.17 ÔìÞìá 8 - ISO/ANSI ÐÏËÕÌÅÓÁ SQL (SQL MULTIMEDIA - SQL/MM)
24. Ôå÷íéêÞ õðïóôÞñéîç ãéá ôçí PostgreSQL
25. ÏéêïíïìéêÜ êáé ÅðáããåëìáôéêÜ ÈÝìáôá
26. Ëßóôá Üëëùí âÜóåùí äåäïìÝíùí
27. ×ñÞóéìåò óõìâïõëÝò ãéá áíáæçôÞóåéò óôï Internet World Wide Web
28. ÓõìðÝñáóìá
29. Óõ÷íÜ ÄéáôõðùìÝíåò ÅñùôÞóåéò ó÷åôéêÜ ìå ôçí PostgreSQL
30. Óçìåßùóç Ðíåõìáôéêþí ÄéêáéùìÜôùí
31. ÐáñÜñôçìá A - Óýíôáîç ôïõ ANSI/ISO SQL 1992
32. ÐáñÜñôçìá B - Ïäçãüò ÅêìÜèçóçò SQL ãéá áñ÷Üñéïõò
32.1 Ïäçãüò ÅêìÜèçóçò ãéá PostgreSQL
32.2 Äåßêôåò Internet äéåõèýíóåùí
33. Appendix C - Ïäçãßåò ãéá ãñÞãïñç åãêáôÜóôáóç Linux
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[1m1. ÅéóáãùãÞ[0m
Ï óêïðüò áõôïý ôïõ êåéìÝíïõ åßíáé íá äþóåé êáôáíïçôïýò äåßêôåò/URLs
ãéá íá óôÞóåôå ãñÞãïñá ôçí PostgreSQL êáé åðßóçò íá õðåñáóðéóôåß ôá
ðëåïíåêôÞìáôá åíüò Áíïéêôïý ÓõóôÞìáôïò Ðçãáßïõ Êþäéêá (Open Source
Code) üðùò ç PostgreSQL, Linux.
ÊÜèå óýóôçìá õðïëïãéóôÞ óôïí êüóìï ÷ñåéÜæåôáé ìéá âÜóç äåäïìÝíùí ãéá
íá áðïèçêåýåé /áíáêôÜ ðëçñïöïñßåò. Ï êýñéïò ëüãïò ðïõ ÷ñçóéìïðïéïýìå
ôïí õðïëïãéóôÞ åßíáé ãéá íá áðïèçêåýïõìå, íá áíáêôïýìå êáé íá
åðåîåñãáæüìáóôå ôçí ðëçñïöïñßá êáé íá ôá êÜíïõìå üëá áõôÜ ãñÞãïñá,
åîïéêïíïìþíôáò Ýôóé ÷ñüíï. Ôáõôü÷ñïíá, ôï óýóôçìá ðñÝðåé íá åßíáé
áðëü, áîéüðéóôï, ïéêïíïìéêü êáé ðïëý åýêïëï óôç ÷ñÞóç ôïõ. Ç ÂÜóç
ÄåäïìÝíùí åßíáé [1mÓÕÓÔÇÌÁ ÆÙÔÉÊÇÓ ÓÇÌÁÓÉÁÓ [22mãéá êÜèå åôáéñßá óôïí êüóìï
ìéá êáé óå áõôÞ áðïèçêåýïíôáé ðïëý óçìáíôéêÝò ðëçñïöïñßåò. Ôá ðéï
äçìïöéëÞ óõóôÞìáôá âÜóåùí äåäïìÝíùí âáóßæïíôáé óôéò SQL ðñïäéáãñáöÝò
ôïõ Äéåèíïýò Ïñãáíéóìïý Ðñïôýðùí ISO (International Standard
Organisation) ïé ïðïßåò âáóßæïíôáé ìå ôç óåéñÜ ôïõò óôo ðñüôõðï ANSI
SQL (ÁìåñéêÜíéêï). Ïé ôñÝ÷ïõóåò ðñïäéáãñáöÝò ðïõ ÷ñçóéìïðïéïýíôáé
åõñÝùò åßíáé ïé ISO/ANSI SQL 1992. Ôï ìåëëïíôéêü ðñüôõðï åßíáé ôï SQL
1998/99 ãíùóôü êáé óáí SQL-3 êáé áíáðôýóóåôáé áêüìç. Äçìïöéëåßò âÜóåéò
üðùò ç Oracle, ç Sybase êáé Informix åßíáé óõóôÞìáôá âáóéóìÝíá óå áõôÜ
ôá ðñüôõðá Þ ðñïóðáèïýí íá ôá õëïðïéÞóïõí.
¼ðùò öáßíåôáé óå áõôü ôï êåßìåíï, õðÜñ÷ïõí ðåñéóóüôåñá áðü 20
äéáöïñåôéêÜ óõóôÞìáôá âÜóåùí äåäïìÝíùí, åìðïñéêÜ/âáóéóìÝíá óôï
internet, ðïõ ÷ñçóéìïðïéïýíôáé óå üëï ôïí êüóìï êáé ðïëëÜ ðåñéóóüôåñá
èá åìöáíéóôïýí óôï ðñïóå÷Ýò ìÝëëïí. ×ùñßò Ýíá ðñüôõðï üðùò ôï
ANSI/ISO SQL, èá Þôáí ðïëý äýóêïëï ãéá ôïí ðåëÜôç íá áíáðôýîåé ìéá
åöáñìïãÞ ìéá ìüíï öïñÜ êáé íá ôç ôñÝ÷åé óå üëá ôá óõóôÞìáôá âÜóåùí
äåäïìÝíùí. Ï óçìåñéíüò ðåëÜôçò èÝëåé íá áíáðôýîåé ìéá åöáñìïãÞ ìéá
öïñÜ ÷ñçóéìïðïéþíôáò ISO SQL, ODBC, JDBC êáé íá ôçí ðïõëÞóåé þóôå íá
÷ñçóéìïðïéåßôáé óå üëá ôá äéáöïñåôéêÜ óõóôÞìáôá âÜóåùí äåäïìÝíùí óôïí
êüóìï.
Ç äçìïöéëÝóôåñç ðáãêïóìßùò ÄÙÑÅÁÍ âÜóç, ðïõ õëïðïéåß ôìÞìá ôïõ ISO
SQL, ANSI SQL/98, SQL/92 êáé ANSI SQL/89 RDBMS åßíáé ç PostgreSQL. Ç
PostgreSQL åßíáé ç ÁíôéêåéìåíïóôñáöÞò Ó÷åóéáêÞ SQL ÂÜóç åðüìåíçò
ãåíéÜò êáé ôá ìåëëïíôéêÜ ðñüôõðá ANSI SQL üðùò ôï SQL 1998 (SQL-3) êáé
ðÝñá èá áó÷ïëïýíôáé üëï êáé ðåñéóóüôåñï ìå Áíôéêåéìåíïóôñáöåßò ÂÜóåéò
êáé ôýðïõò äåäïìÝíùí ÁíôéêåéìÝíïõ (Object data types). Ç PostgreSQL
åßíáé ôï ìüíï äùñåÜí RDBMS óôïí êüóìï ðïõ õðïóôçñßæåé
Áíôéêåéìåíïóôñáöåßò ÂÜóåéò êáé SQL. Áõôü ôï êåßìåíï èá óáò ðåé ðþò íá
åãêáôáóôÞóåôå ôç âÜóç êáé, åðßóçò, üëá ôá ðáêÝôá ó÷åôéêÜ ìå âÜóåéò,
ðþò íá åãêáôáóôÞóåôå Web database, application database, ãñáöéêÜ
ðñïãñÜììáôá åðéêïéíùíßáò êáé ÷åéñéóìïý (front end GUIs êáé ðñïãñÜììáôá
interface). Óáò óõìâïõëåýïõìå íá ãñÜøåôå ÏÐÙÓÄÇÐÏÔÅ ôéò åöáñìïãÝò
âÜóåùí 100 % óõìâáôÝò ìå ôá ðñüôõðá ISO/ANSI SQL, ODBC, JDBC, Ýôóé
þóôå ç åöáñìïãÞ óáò íá åßíáé ìåôáöÝñóéìç óå ðïëëÝò âÜóåéò üðùò ïé
PostgreSQL, Oracle, Sybase, Informix êëð.
Ìå ôçí PostgreSQL, èá Ý÷åôå ôçí õøçëüôåñç ðïéüôçôá êáé ðïëëÜ Üëëá
÷áñáêôçñéóôéêÜ ìéá êáé áêïëïõèåß ôï 'Áíïéêôü ÌïíôÝëï ÁíÜðôõîçò Ðçãáßïõ
Êþäéêá' (Open Source Code development). Ôï Áíïéêôü ìïíôÝëï ÁíÜðôõîçò
Ðçãáßïõ Êþäéêá åßíáé ôï ìüíï ôïõ ïðïßïõ ìðïñåßôå íá ðÜñåôå üëïí ôïí
ðçãáßï êþäéêá, êáé ç áíÜðôõîç ãßíåôáé óôï internet áðü åîáéñåôéêÜ
ìåãÜëï äßêôõï áíèñþðéíùí ìõáëþí. Ç ìåëëïíôéêÞ ìüäá ðñïâëÝðåé üôé ç
ìåãáëýôåñç áíÜðôõîç ëïãéóìéêïý èá ãßíåôáé óôçí áðïêáëïýìåíç
"Õðåñëåùöüñï Ðëçñïöïñéþí" (Information Super-Highway) ðïõ äéáôñÝ÷åé
üëï ôïí êüóìï. Óôá ÷ñüíéá ðïõ Ýñ÷ïíôáé, ç áíÜðôõîç ôïõ internet èá
åßíáé åêñçêôéêÞ ç ïðïßá ìå ôç óåéñÜ ôçò èá ðõñïäïôÞóåé ôç ãñÞãïñç
õéïèÝôçóç ôçò PostgreSQL áðü ôïõò ðåëÜôåò.
Åöáñìüæïíôáò ôéò áñ÷Ýò ôçò öõóéêÞò (êâáíôïìç÷áíéêÞ, êëáóóéêÞ,
èåñìïäõíáìéêÞ), ôùí ìáèçìáôéêþí êáé ôçò óôáôéóôéêÞò óôçí ðïéüôçôá ôïõ
ëïãéóìéêïý, ðáßñíåôå ôçí õøçëüôåñç ðïéüôçôá ëïãéóìéêïý ìüíï óå Ýíá
'Áíïéêôü Óýóôçìá Ðçãáßïõ Êþäéêá' üðùò ç PostgreSQL áíïßãïíôáò ôïí
ðçãáßï êþäéêá óå Ýíá ðåëþñéï áñéèìü áíèñþðéíùí ìõáëþí äéáóõíäåäåìÝíùí
ìÝóù ôçò Õðåñëåùöüñïõ Ðëçñïöïñéþí. ¼óï ìåãáëýôåñïò ï áñéèìüò ôùí
áíèñþðùí ðïõ åñãÜæïíôáé ðÜíù ó' áõôü, ôüóï êáëýôåñç èá åßíáé ç
ðïéüôçôá ôïõ ëïãéóìéêïý. Ôï Áíïéêôü ÌïíôÝëï Ðçãáßïõ Êþäéêá èá
åìðïäßóåé åðßóçò [1môçí áíáêÜëõøç ôïõ ôñï÷ïý áðü ôçí áñ÷Þ [22m, èá ìåéþóåé [1môç[0m
[1mäéðëÞ äïõëåéÜ [22mêáé èá åßíáé ðïëý ïéêïíïìéêü, èá åîïéêïíïìåß ÷ñüíï óôç
äéáíïìÞ êáé áêïëïõèåß ôïõò íüìïõò ôçò ìïíôÝñíáò ïéêïíïìßáò ãéá
âåëôéóôïðïßçóç ôùí åèíéêþí êáé ãåíéêþí ðüñùí. ¼ôáí ìéá åñãáóßá
ëïãéóìéêïý Ý÷åé ãßíåé áðü Üëëïõò, ôüôå [1mÄÅÍ [22m÷ñåéÜæåôáé íá ôçí êÜíåôå
åóåßò ðÜëé. Äå èá óðáôáëÞóåôå ôïí ðïëýôéìï ÷ñüíï óáò óå êÜôé ðïõ Ý÷åé
Þäç ãßíåé êáëÜ. Êáèþò èá ìðáßíïõìå óôïí 21ï áéþíá, èá õðÜñ÷åé áëëáãÞ
óôïí ôñüðï ðïõ ðáßñíïõìå ôï ëïãéóìéêü ãéá ÷ñÞóç. Ïé ðåëÜôåò èá
ðñïôéìïýí ôá áíïéêôÜ óõóôÞìáôá ëïãéóìéêïý üðùò ç PostgreSQL, ôï Linux
êëð.
Áí áãïñÜóåôå åêôåëÝóéìá ðñïãñÜììáôá, äå èá ðÜñåôå êáé ôïí êþäéêá êáé
ôá äéêáéþìáôÜ ôïõ. Ï ðçãáßïò êþäéêáò åßíáé áíåêôßìçôï óôïé÷åßï åíþ ôá
åêôåëÝóéìá äåí Ý÷ïõí êáìéÜ áîßá. Ôï íá áãïñÜóåôå ëïãéóìéêü [4mìðïñåß[24m íá
áíÞêåé óôï ðáñåëèüí. Ãéá íá áãïñÜóåôå êáëü õëéêü (hardware), áîßæåé
íá îïäÝøåôå ÷ñÞìáôá êáé íá ðÜñåôå ôï ëïãéóìéêü áðü ôï internet.
Óçìáíôéêü óçìåßï åßíáé ôï õëéêü ôïõ õðïëïãéóôÞ ôï ïðïßï [1mêÜíåé ôïí[0m
[1mêýñéï üãêï ôçò äïõëåéÜò[22m. To õëéêü åßíáé ôï Üëïãï ðïõ êÜíåé ôç äïõëåéÜ
åíþ ôï ëïãéóìéêü áðëÜ ôï ïäçãåß. Ôï õëéêü ôùí õðïëïãéóôþí åßíáé ðïëý
ðïëýðëïêï êáé ìüíï 6 áðü ôéò 180 ÷þñåò óôïí êüóìï ìÝ÷ñé ôþñá Ý÷ïõí
åðéäåßîåé ôçí éêáíüôçôá ó÷åäéáóìïý êáé êáôáóêåõÞò ðëáêåôþí/õëéêïý
õðïëïãéóôþí. Ï ó÷åäéáóìüò êáé ç êáôáóêåõÞ chips õðïëïãéóôþí åßíáé
ðñïçãìÝíç ôå÷íïëïãßá. Åßíáé ìéá ðïëý óýíèåôç äéáäéêáóßá, äáðáíçñÞ,
áðáéôåß ìåãÜëåò åðåíäýóåéò óå åñãïóôÜóéá êáé ìç÷áíÝò ðáñáãùãÞò ðïõ
äïõëåýïõí ìå ôå÷íïëïãßá 0.18 micron. Óå Ýíá ìéêñü chip óéëéêüíçò
åêáôïììýñéá ôñáíæßóôïñò/êõêëþìáôá åßíáé óôåíÜ ðáêåôáñéóìÝíá. Åôáéñåßåò
üðùò ïé AMD, Intel, Cyrix, Hitachi, IBM êáé Üëëåò îüäåøáí óçìáíôéêü
áñéèìü áðü áíèñùðï÷ñüíéá ãéá íá ãßíïõí êýñéïé õøçëþí ôå÷íïëïãéþí üðùò
ç ìéêñïçëåêôñïíéêÞ (Micro-electronics) êáé ç íáíïçëåêôñïíéêÞ (Nano-
electronics). Micro óçìáßíåé (Ýíá-åêáôïììõñéïóôü ôïõ ìÝôñïõ 10^-6),
Nano óçìáßíåé (Ýíá-äéóåêáôïììõñéïóôü ôïõ ìÝôñïõ 10^-9). Ç ôñÝ÷ïõóá
ôå÷íïëïãßá ÷ñçóéìïðïéåß ìéêñïçëåêôñïíéêÞ ãýñù óôá 0.35 micron
÷ñçóéìïðïéþíôáò áãùãïýò áëïõìéíßïõ, êáé ìåãÝèç ôùí 0.25 micron
÷ñçóéìïðïéþíôáò áãùãïýò çëåêôñïíßùí áðü ÷áëêü. Óôï êïíôéíü ìáò ìÝëëïí
èá ÷ñçóéìïðïéçèåß ôå÷íïëïãßá ôùí 0.10 micron ìå ÷áëêü êáé
íáíïçëåêôñïíéêÞ ãéá íá öôéÜîïõí ôóéðÜêéá õðïëïãéóôÞ. Ïé áãùãïß
áëïõìéíßïõ èá áíôéêáôáóôáèïýí áðü ÷áëêü óôá chips ôùí õðïëïãéóôþí,
êáèþò ï ÷áëêüò åßíáé êáëýôåñïò áãùãüò ôùí çëåêôñïíßùí. Óôç
öùôïëéèïãñáößá, èá ÷ñçóéìïðïéçèïýí ôå÷íéêÝò õðåñéþäïõò áêôéíïâïëßáò,
áêôßíåò × Þ äÝóìçò çëåêôñïíßùí ãéá ÷Üñáîç êõêëùìÜôùí ìå ìåëëïíôéêÜ
ìåãÝèç ìéêñüôåñá ôùí 0.15 micron.
Óå 20 ÷ñüíéá áðü ôþñá, ôá ôóéð óéëéêüíçò èá áíôéêáôáóôáèïýí áðü
ìïñéáêïýò õðïëïãéóôÝò êáé âéïôóéðò ðïõ èá åßíáé äéóåêáôïììýñéá öïñÝò
ãñçãïñüôåñá áðü ôá ôóéð óéëéêüíçò. Ôá ìüñéá åßíáé Ýíá óýíïëï áôüìùí.
Êáé ôá Üôïìá åßíáé ôá ìéêñÜ óùìáôßäéá ðïõ áðïôåëïýí ü,ôé âëÝðåôå óå
áõôü ôïí êüóìï. Ïé ìïñéáêïß õðïëïãéóôÝò èá ÷ñçóéìïðïéïýí ôá ìüñéá ôçò
ýëçò óáí õðåñãñÞãïñïõò äéáêüðôåò on/off. ¼ôáí ï äéáêüðôçò åßíáé ON
óçìáßíåé 1, êáé üôáí åßíáé OFF óçìáßíåé 0. ¼ëá ôá ðñïãñÜììáôá óå áõôüí
ôïí êüóìï âáóßæïíôáé óôï äõáäéêü óýóôçìá.
Ï ðáñáêÜôù ðßíáêáò äåß÷íåé ôç ðñüïäï êáé ôéò ìåëëïíôéêÝò ôÜóåéò
ðñïüäïõ ôùí chips ôùí õðïëïãéóôþí.
Advancement of chip capabilities in future
********************************************
+--------------------------+---------+---------+---------+---------+--------+---------+
| Item/Year | 1997 | 1999 | 2001 | 2003 | 2012 | 2020 |
+--------------------------+---------+---------+---------+---------+--------+---------+
| Feature size(micron) | 0.25 | 0.18 | 0.15 | 0.13 | 0.05 |< 0.00001|
+--------------------------+---------+---------+---------+---------+--------+---------+
| Wafer size(mm) | 200 | 300 | 300 | 300 | 450 | Mol/Bio |
+--------------------------+---------+---------+---------+---------+--------+---------+
| Min Operating Voltage | 1.8-2.5 | 1.5-1.8 | 1.2-1.5 | 1.2-1.5 | 0.5-0.6| < 0.001 |
+--------------------------+---------+---------+---------+---------+--------+---------+
| Max power dissipation | 70 | 90 | 110 | 130 | 175 | 600 |
+--------------------------+---------+---------+---------+---------+--------+---------+
| On-chip frequencey (MHz) | 750 | 1,250 | 1,500 | 2,100 | 10,000 | > 50,000|
+--------------------------+---------+---------+---------+---------+--------+---------+
| DRAM capacity | 256 MB | 1 GB | 2 GB | 4 GB | 256 GB | > 1000GB|
+--------------------------+---------+---------+---------+---------+--------+---------+
¼ðùò âëÝðåôå, ôï õëéêü åßíáé õøçëÞò ôå÷íïëïãßáò êáé óçìáíôéêü åíþ ôï
ëïãéóìéêü åßíáé ëéãüôåñï äýóêïëç ôå÷íïëïãßá. Áñá, ç êáôáóêåõÞ
õëéêïý/õëéêþí-áãáèþí åßíáé æùôéêÞò óçìáóßáò ãéá ôçí åèíéêÞ ïéêïíïìßá!
Åôáéñåßåò üðùò ïé Compaq, Dell, Sun Microsystems, HP, IBM ðïõ
êáôáóêåõÜæïõí õðïëïãéóôÝò åßíáé ïé êýñéïé óõíåéóöÝñïíôåò óôçí
ïéêïíïìßá ôçò ÁìåñéêÞò óÞìåñá êáé óôï ìÝëëïí!!
Áðü ôçí Üëëç, êÜèå ÷þñá áíåîáéñÝôùò óôïí êüóìï áíáðôýóóåé/öôéÜ÷íåé
ëïãéóìéêü. Óôçí ðñáãìáôéêüôçôá, ïðïéïóäÞðïôå óôïí êüóìï ìå Ýíá ìéêñü
PC ÷áìçëïý-êüóôïõò ìðïñåß íá äçìéïõñãÞóåé Ýíá óýóôçìá ìéáò âÜóçò
äåäïìÝíùí óáí ôçí Oracle . ÁëëÜ èá ôïõ Ýðáéñíå 10 ÷ñüíéá (ï
äéáêïìéóôÞò ôçò Oracle åßíáé ðåñßðïõ 10 áíèñùðï-Ýôç äïõëåéÜ). ¸íá
áíèñùðï-Ýôïò åßíáé Ýíá Üôïìï ðïõ äïõëåýåé ìå ðëÞñç áðáó÷üëçóç ãéá Ýíá
ïëüêëçñï Ýôïò. Áí 10 Üíèñùðïé åñãÜæïíôáé ãéá 10 Ýôç ôüôå Ý÷ïõí
îïäåõôåß 10 áíèñùðï-Ýôç.
ÂÜóåéò üðùò ïé Oracle, Informix, Sybase, IBM DB2 (Unix) ãñÜöôçêáí óå
ãëþóóá "C" êáé ôá åêôåëÝóéìá äçìéïõñãÞèçêáí ìåôáãëùôôßæïíôáò ôïí
êþäéêá êáé ìåôÜ áðïóôÜëèçêáí óôïõò ðåëÜôåò. Ïé âÜóåéò Oracle, Sybase,
Informix åßíáé ðñïãñÜììáôá 100 % "C"!!
Ìéá êáé Ý÷åé ãßíåé ðïëëÞ äïõëåéÜ óôçí PostgreSQL ôá ôåëåõôáßá 12
÷ñüíéá, äåí Ý÷åé íüçìá îáíáäçìéïõñãÞóïõìå áðü ôçí áñ÷Þ ìéá Üëëç âÜóç
ðïõ íá éêáíïðïéåß ôï ðñüôõðï ANSI/ISO SQL. Åßíáé ìåãÜëï ðëåïíÝêôçìá íá
÷ñçóéìïðïéÞóïõìå ôïí õðÜñ÷ïíôá êþäéêá êáé íá ðñïóèÝóïõìå ôá
÷áñáêôçñéóôéêÜ ðïõ ëåßðïõí Þ ðñïóèÞêåò óôçí PostgreSQL êáé íá
áñ÷ßóïõìå íá ôç ÷ñçóéìïðïéïýìå áìÝóùò.
Ç PostgreSQL äåí åßíáé áðëÜ ìéá äùñåÜí âÜóç áëëÜ Ýíá êáëÞò ðïéüôçôáò
'Ðñïúüí Internet'. ÐñïâëÝðåôáé üôé ç æÞôçóç ðñïúüíôùí "Made By
Internet" èá áõîçèåß åêèåôéêÜ ìéá êáé åßíáé éêáíü íá äéáôçñåß õøçëÞ
ðïéüôçôá, ÷áìçëü êüóôïò, åîáéñåôéêÜ ìåãÜëç âÜóç ÷ñçóôþí êáé áôüìùí ðïõ
áíáðôýóóïõí êþäéêá. ÁõôÜ ôá Ýèíç ðïõ äå ÷ñçóéìïðïéïýí ôá ðñïúüíôá
'Made By Internet' èá ÷Üóïõí óïâáñÜ ôçí "ÅðáíÜóôáóç World-wide
Internet" êáé èá ìåßíïõí ðïëý ðßóù áðü ôéò Üëëåò ÷þñåò. Ï ëüãïò åßíáé
üôé ôï ßäéï ôï "Internet" åßíáé ç [1mìåãáëýôåñç [22måôáéñåßá ðáñáãùãÞò
ëïãéóìéêïý óå üëï ôïí êüóìï!
[1m2. ¶ëëåò ÌïñöÝò áõôïý ôïõ êåéìÝíïõ[0m
Áõôü ôï êåßìåíï åßíáé ôõðùìÝíï óå 10 äéáöïñåôéêÝò ìïñöÝò, ïíïìáóôéêÜ -
DVI, Postscript, Latex, LyX, GNU-info, HTML, RTF (Rich Text Format),
Plain-text, Óåëßäåò âïçèåßáò Unix (Unix man pages) êáé SGML.
· Ìðïñåßôå íá ðÜñåôå áõôü ôï êåßìåíï HOWTO óáí Ýíá áñ÷åßï tar óå
ìïñöÞ HTML, DVI, Postscript Þ SGML áðü ôï -
<ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/other-formats/>
· Ç áðëÞ ìïñöÞ êåéìÝíïõ âñßóêåôáé óôï:
<ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO>
· Ãéá ó÷üëéá, ðáñáôçñÞóåéò, äéïñèþóåéò, åíçìåñþóåéò ðåñß ôçò
ÅëëçíéêÞò ìåôÜöñáóçò áõôïý ôïõ HOWTO, óôåßëôå email óôçí Âïýëá
ÓáíéäÜ : voulariba@hellug.gr Þ óôïí Åõñéðßäç Ðáðáêþóôá :
evris@hellug.gr êáé åíáëëáêôéêÜ : ep@rocketmail.com
· ÌåôáöñÜóåéò óå Üëëåò ãëþóóåò üðùò ÃáëëéêÜ, ÃåñìáíéêÜ, ÉóðáíéêÜ,
ÊéíÝæéêá, ÃéáðùíÝæéêá âñßóêïíôáé óôï
<ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO> ÏðïéáäÞðïôå âïÞèåéá
ãéá ìåôÜöñáóç óå Üëëåò ãëþóóåò åßíáé åõðñüóäåêôç.
Ôï êåßìåíï ãñÜöôçêå ÷ñçóéìïðïéþíôáò ôá "åñãáëåßá SGML" ôá ïðïßá èá
ôá âñåßôå óôï - <http://www.xs4all.nl/~cg/sgmltools/> Áöïý
ìåôáãëùôôßóåôå ôïí êþäéêá èá Ý÷åôå åíôïëÝò üðùò
· sgml2html databasehowto.sgml (ãéá íá äçìéïõñãÞóåôå áñ÷åßá html)
· sgml2rtf databasehowto.sgml (ãéá íá äçìéïõñãÞóåôå áñ÷åßá RTF)
· sgml2latex databasehowto.sgml (ãéá íá äçìéïõñãÞóåôå áñ÷åßá
latex)
Ôï êåßìåíï âñßóêåôáé óôï -
· <http://sunsite.unc.edu/LDP/HOWTO/PostgreSQL-HOWTO.html>
Ìðïñåßôå åðßóçò íá âñåßôå ôï êåßìåíï óôá ðáñáêÜôù mirrors sites -
· <http://www.caldera.com/LDP/HOWTO/PostgreSQL-HOWTO.html>
· <http://www.WGS.com/LDP/HOWTO/PostgreSQL-HOWTO.html>
· <http://www.cc.gatech.edu/linux/LDP/HOWTO/PostgreSQL-HOWTO.html>
· <http://www.redhat.com/linux-info/ldp/HOWTO/PostgreSQL-HOWTO.html>
· ¶ëëá mirror sites êïíôÜ óáò (network-address-wise) ìðïñåßôå íá
âñåßôå óôï <http://sunsite.unc.edu/LDP/hmirrors.html> äéáëÝîôå Ýíá
site êáé ðçãáßíåôå óôïí êáôÜëïãï /LDP/HOWTO/PostgreSQL-HOWTO.html
Ãéá íá äåßôå ôï êåßìåíï óå ìïñöÞ dvi, ÷ñçóéìïðïéÞóôå ôï ðñüãñáììá
xdvi. Ôï ðñüãñáììá xdvi âñßóêåôáé óôï ðáêÝôï tetex-xdvi*.rpm óôï
Redhat Linux ôï ïðïßï âñßóêåôáé óôá êïõìðéÜ ControlPanel |
Applications | Publishing | TeX menu. Ãéá íá äéáâÜóåôå êåßìåíï dvi
äþóôå ôçí åíôïëÞ -
xdvi -geometry 80x90 howto.dvi
êáé áëëÜîôå ôï ìÝãåèïò ôïõ ðáñáèýñïõ ìå ôï ðïíôßêé. Äåßôå ôç óåëßäá
âïÞèåéáò ãéá ôï xdvi.
Ãéá íá ìåôáêéíçèåßôå ÷ñçóéìïðïéÞóôå ôá âåëÜêéá, ôá ðëÞêôñá Page Up,
Page Down, ìðïñåßôå íá ÷ñçóéìïðïéÞóåôå åðßóçò ôá ãñÜììáôá 'f', 'd',
'u', 'c', 'l', 'r', 'p', 'n' ãéá íá ìåôáêéíçèåßôå ðñïò ôá ðÜíù, êÜôù,
óôï êÝíôñï, óôçí åðüìåíç óåëßäá, óôçí ðñïçãïýìåíç óåëßäá êëð.
Ãéá íá áðåíåñãïðïéÞóåôå ôï expert ìåíïý ðáôÞóôå 'x'. Ìðïñåßôå íá
äéáâÜóåôå áñ÷åßá postscript ÷ñçóéìïðïéþíôáò ôï 'gv' (ghostview) Þ
'ghostscript'. Ôï ðñüãñáììá ghostscript âñßóêåôáé óôï ðáêÝôï
ghostscript*.rpm êáé ôï ðñüãñáììá gv óôï ðáêÝôï gv*.rpm óôï Redhat
Linux ôï ïðïßï âñßóêåôáé óôá êïõìðéÜ ôùí ìåíïý ControlPanel |
Applications | Graphics. Ôï ðñüãñáììá gv åßíáé ðïëý ðéï öéëéêü óôï
÷ñÞóôç áðü ôï ghostscript. Ôï ghostscript êáé ôï gv åßíáé åðßóçò
äéáèÝóéìá êáé óå Üëëåò ðëáôöüñìåò üðùò óå OS/2, Windows 95 êáé NT,
âëÝðåôå áõôü ôï êåßìåíï áêüìç êáé óå áõôÝò ôéò ðëáôöüñìåò.
Ãéá íá äéáâÜóåôå êåßìåíï postscript äþóôå ôçí åíôïëÞ -
gv howto.ps
Ãéá íá ÷ñçóéìïðïéÞóåôå ôï ghostscript ôçí åíôïëÞ -
ghostscript howto.ps
[1mÐÑÏÓÏ×Ç: [22mÔï êåßìåíï áõôü åßíáé ìåãÜëï, ï óõíïëéêüò áñéèìüò óåëßäùí (óå
postscript) áí ôõðùèåß èá åßíáé ðåñßðïõ 113 óåëßäåò óôá ÁããëéêÜ (óôá
åëëçíéêÜ èá ðñÝðåé íá åßíáé ðåñéóóüôåñåò).
Ìðïñåßôå íá äéáâÜóåôå ôï êåßìåíï óå ìïñöÞ HTML ÷ñçóéìïðïéþíôáò
Netscape Navigator, Microsoft Internet explorer, Redhat Baron Web
browser Þ ïðïéïäÞðïôå áðü ôïõò Üëëïõò 10 web browsers.
Ìðïñåßôå íá äéáâÜóåôå ôçí Ýîïäï ôïõ óå latex, LyX ÷ñçóéìïðïéþíôáò ôï
LyX, Ýíá X-Windows ãñáöéêü ðñüãñáììá äéáóýíäåóçò ìå latex.
[1m3. Ïé íüìïé ôçò ÖõóéêÞò åöáñìüæïíôáé óôï ëïãéóìéêü![0m
Óå áõôü ôï êåöÜëáéï, èá óáò äåßîïõìå ðþò ç åðéóôÞìç ðáßæåé óçìáíôéêü
ñüëï óôç äçìéïõñãßá äéáöüñùí áíôéêåéìÝíùí üðùò ôï ëïãéóìéêü, ôï
óýìðáí, ôá Üôïìá, ôçí åíÝñãåéá áêüìá êáé åóÜò ôïõò ßäéïõò! Áõôü ôï
êåöÜëáéï èá óáò äåßîåé åðßóçò ãéáôß ç ãíþóç ôçò åðéóôÞìçò åßíáé ðïëý
óçìáíôéêÞ ÐÑÉÍ íá îåêéíÞóåôå íá ÷ñçóéìïðïéåßôå ôá ðñïúüíôá ôçò. Ôá
áíôéêåßìåíá ðåñéëáìâÜíïõí ï,ôéäÞðïôå - ãéá ðáñÜäåéãìá ç PostgreSQL, ï
÷ñüíïò, ç ìÜæá, ç åíÝñãåéá, ïé ðëáíÞôåò, ï Þëéïò, ôï öåããÜñé, ôá
áóôÝñéá, ïé ãáëáîßåò, ïé Üíèñùðïé êëð... åßíáé áíôéêåßìåíá
äçìéïõñãÞìáôá ôçò åðéóôÞìçò. Áõôü ôï êåöÜëáéï ðåñéãñÜöåé åðßóçò ðþò
ïé íüìïé ôçò åðéóôÞìçò êáé ç óôáôéóôéêÞ åõíïïýí ôá óõóôÞìáôá open-
source code üðùò ç PostgreSQL êáé ôï Linux. Êáèþò ç ôá÷ýôçôá óôï
äéáäßêôõï áõîÜíåôáé êáèçìåñéíÜ, êáé ôï äéáäßêôõï ãßíåôáé ïëïÝíá êáé
ðéï óôáèåñü, ôá óõóôÞìáôá open-source code ãíùñßæïõí ãñÞãïñç áíÜðôõîç.
Êáé áí ïé óôáôéóôéêïß êáíüíåò êáé ïé íüìïé ôçò öõóéêÞò åßíáé óùóôïß,
ôá óõóôÞìáôá closed source-code èá áöáíéóôïýí ôåëéêÜ áðü ôïí ðëáíÞôç.
Ïé ðáñÜãñáöïé ðïõ áêïëïõèïýí ðáñáêÜôù èá óáò äåßîïõí - "ðüóï áðÝñáíôç
åßíáé ç åðéóôÞìç, ðüóï óçìáíôéêÞ åßíáé ãéá ôïí Üíèñùðï êáé ðþò åðéäñÜ
óå Ýñãá ëïãéóìéêïý üðùò ç PostgreSQL, ôï Linux".
Ôï íá áíáðôýîåôå Ýíá project üðùò ç PostgreSQL, áðáéôåß åíÝñãåéá êáé
÷ñüíï, Üñá ç PostgreSQL åßíáé ðñïúüí åíÝñãåéáò êáé ÷ñüíïõ. Ìéá êáé ç
åíÝñãåéá êáé ï ÷ñüíïò ìðïñïýí íá åîçãçèïýí ìüíï åðéóôçìïíéêÜ, õðÜñ÷åé
ìéá áìößäñïìç ó÷Ýóç ìåôáîý ôçò öõóéêÞò êáé ôùí Ýñãùí ëïãéóìéêïý üðùò ç
PostgreSQL, ôï Linux.
Ïé åðéóôçìïíéêïß íüìïé (ÖõóéêÞ) åöáñìüæïíôáé ðáíôïý, óõíÝ÷åéá, óå ü,ôé
êÜíåôå áêüìç êáé óôá Ýñãá ëïãéóìéêïý üðùò óõóôÞìáôá âÜóåùí äåäïìÝíùí.
Ç ÖõóéêÞ åöáñìüæåôáé áêüìç êáé üôáí ìéëÜôå (ç÷çôéêÜ êýìáôá), ðåñðáôÜôå
(ôñéâÞ ìåôáîý åäÜöïõò êáé ðÝëìáôïò), äéáâÜæåôå Ýíá âéâëßï Þ ãñÜöåôå
ëïãéóìéêü. Ðïëëïß êëÜäïé ôçò åðéóôÞìçò üðùò ç öõóéêÞ, ç ÷çìåßá êëð.
óõã÷ùíåýïíôáé óå ìéá åõñåßá ðåñéï÷Þ, ôá ÌáèçìáôéêÜ (åðßóçò ãíùóôÜ êáé
óáí ôç Âáóßëéóóá üëùí ôùí Åðéóôçìþí). ÏôéäÞðïôå óå áõôü ôïí êüóìï
Ý÷åé âáèéÝò ñßæåò óôá ìáèçìáôéêÜ, óõìðåñéëáìâáíïìÝíçò ôçò PostgreSQL.
Ç PostgreSQL ÷ñçóéìïðïéåß ôç 'ÌïíôÝñíá ¶ëãåâñá' ,Ýíá ðïëý ìéêñü
ðáñáêëÜäé ôùí ìáèçìáôéêþí . Ç 'ÌïíôÝñíá ¶ëãåâñá' áó÷ïëåßôáé ìå ôç
'Èåùñßá Óõíüëùí', ôç 'Ó÷åóéáêÞ ¶ëãåâñá', åðéóôÞìç ôùí Groups, Rings,
Collections, Sets, Unions, Intersections, Exclusions, Domains, Lists,
êëð...
Ëïãéóìéêü üðùò ç PostgreSQL õðÜñ÷åé óÞìåñá ëüãù ôçò åíÝñãåéáò êáé ôïõ
÷ñüíïõ. Ç åíÝñãåéá åßíáé áõôÞ ðïõ äçìéïýñãçóå ôïí êüóìï, ôïí
áíèñþðéíï åãêÝöáëï êáé ðïëëÜ Üëëá ðñÜãìáôá! Ç ìÜæá êáé ç åíÝñãåéá
åßíáé ç [1mÉÄÉÁ [22mÏÍÔÏÔÇÔÁ! Ôï ãåãïíüò üôé ç ìÜæá êáé ç åíÝñãåéá åßíáé ôï
ßäéï ðñÜãìá Þôáí Üãíùóôï óôïõò áíèñþðïõò 100 ÷ñüíéá ðñéí!
Ïé êõøÝëåò óôïí áíèñþðéíï åãêÝöáëï êáôáíáëþíïõí åíÝñãåéá êáèþò
åðåîåñãÜæïíôáé (ðáñÜãïõí ëïãéóìéêü) ìåôáôñÝðïíôáò ôç ÷çìéêÞ åíÝñãåéá
óå èåñìéêÞ åíÝñãåéá. Áêüìç êáé ôþñá ðïõ äéáâÜæåôå áõôÞ ôçí ðáñÜãñáöï,
ïé êõøÝëåò óôïí åãêÝöáëü óáò êáßíå âåíæßíç êáé ÷ñçóéìïðïéïýí ôçí
åíÝñãåéá. Ãé' áõôü ÓÔÁÌÁÔÇÓÔÅ ÍÁ ÄÉÁÂÁÆÅÔÅ ÔÙÑÁ! Ç åíÝñãåéá ôùí
íåõñþíùí (êõøÝëåò óôïí åãêÝöáëï) ìðïñåß íá ìåôñçèåß óôá åñãáóôÞñéá.
Ãéá ðáñÜäåéãìá, õðÜñ÷ïõí ðïëëÜ üñãáíá üðùò ïé "Áíé÷íåõôÝò ØåìÜôùí" êáé
Üëëá éáôñéêÜ üñãáíá ðïõ ìðïñïýí íá ìåôñÞóïõí ôçí åíÝñãåéá ðïõ
êáôáíáëþíåé ï åãêÝöáëïò.
¼ëá áõôÜ õðïíïïýí üôé ï áíèñþðéíïò åãêÝöáëïò åßíáé ìéá èåñìïäõíáìéêÞ
ðçãÞ åíÝñãåéáò. ÅðåéäÞ ï Üíèñùðïò åßíáé ìéá èåñìïäõíáìéêÞ ðçãÞ
åíÝñãåéáò, ïé íüìïé ôçò èåñìïäõíáìéêÞò åöáñìüæïíôáé óôïí åãêÝöáëï êáé
Ýôóé ç èåñìïäõíáìéêÞ Ý÷åé Ýììåóá áðïôåëÝóìáôá óå ëïãéóìéêü üðùò ç
PostgreSQL.
¼ðùò óå êÜèå åðéóôÞìç, åßíáé áäýíáôï íá ÷ôßóåôå ïðïéïäÞðïôå óýóôçìá Þ
èåùñßá (óõìðåñéëáìâáíïìÝíïõ åíüò óõóôÞìáôïò âÜóåùí äåäïìÝíùí) ðïõ íá
åßíáé 100 % ôÝëåéï êáé ÷ùñßò óöÜëìáôá. Åßíáé óá íá êõíçãÜôå Ýíáí
áíåìïóôñüâéëï , äå èá êáôáöÝñïõìå [1mÐÏÔÅ [22míá öôéÜîïõìå ôï ôÝëåéï óýóôçìá
Þ èåùñßá. Ëåðôïìåñåßò ìáèçìáôéêÝò åîéóþóåéò/óõæçôÞóåéò ãéá ôçí
áðüäåéîç ôçò ýðáñîçò åíüò 'ôÝëåéïõ óõóôÞìáôïò' åßíáé áäýíáôï íá ãßíïõí
åäþ êáèþò îåðåñíÜ ôï óêïðü áõôïý ôïõ êåéìÝíïõ.
Êáé ìéá ôÝôïéá ìáèçìáôéêÞ óõæÞôçóç áó÷ïëåßôáé ìå ôïí Üðåéñï áñéèìü
äéáóôÜóåùí ðïõ õðÜñ÷ïõí óôç öýóç. Äõóôõ÷þò, ïé Üíèñùðïé ìðïñïýí íá
äïõí Þ íá íéþóïõí 4 äéáóôÜóåéò áëëÜ ôá ìáèçìáôéêÜ ìðïñïýí íá
åîåñåõíÞóïõí åýêïëá êáé Üëëåò äéáóôÜóåéò.
¶ëëåò äéáóôÜóåéò åßíáé [1m'Üðåéñá ìéêñüôåñåò' [22máðü ôá Üôïìá êáé ôá ßäéá ôá
Üôïìá åßíáé ìå ôç óåéñÜ ôïõò ðïëý ìéêñÜ êáé ôï áíèñþðéíï ìÜôé äå
ìðïñåß íá ôá îå÷ùñßóåé! Ôá ÌáèçìáôéêÜ åßíáé ðïëý éó÷õñÜ ìéá êáé
ìðïñïýí íá áíáëýóïõí êáé íá åîçãÞóïõí ôç ãÝííçóç/ èÜíáôï üëçò ôçò
õöçëßïõ. Ï êüóìïò ìáò Ý÷åé ó÷åäüí [1mìçäåíéêü ìÝãåèïò [22máí ôïí êïéôÜîåôå
áðü Üëëï óýìðáí êáé áíôßóôñïöá. Áõôü óçìáßíåé üôé ï êüóìïò ìáò äåí
åßíáé ïñáôüò (äåí õðÜñ÷åé) ãéá ôá Üôïìá ðïõ âñßóêïíôáé óå Üëëï óýìðáí.
Êáé áíôßóôñïöá! ÈåùñçôéêÜ, ìðïñåßôå íá âãåßôå áðü ôïí êüóìï ìáò êáé
íá ôáîéäÝøåôå ìåãÜëåò áðïóôÜóåéò (äéóåêáôïììýñéá Ýôç öùôüò) óå
åëÜ÷éóôï ÷ñüíï êáé íá îáíáìðåßôå óôïí êüóìï ìáò óå Ýíá äéáöïñåôéêü
óçìåßï ôïõ ÷ùñï÷ñüíïõ! Ç áðüóôáóç ìåôáîý ôïõ êüóìïõ ìáò êáé ôùí Üëëùí
êüóìùí åßíáé ðñáãìáôéêÜ ìçäåíéêüò!
Áêüìç êáé áí õðÜñ÷åé Üðåéñïò áñéèìüò äéáóôÜóåùí, ìðïñïýí üëåò íá
ðñïêýøïõí/ äçìéïõñãçèïýí áðü Ýíá ìéêñü áñéèìü ÊÕÑÉÙÍ äéáóôÜóåùí.
¶ðåéñïò áñéèìüò äéáóôÜóåùí ìðïñïýí íá óõíäõáóôïýí êáé íá êáôáëÞîïõí
óå êýñéåò äéáóôÜóåéò. Ïé êýñéåò äéáóôÜóåéò áðëÜ áðïññïöïýí ôéò Üëëåò
äéáóôÜóåéò ÷ùñßò áõôÝò íá êáôáóôñÝöïíôáé. Ïé ìáèçìáôéêïß
÷ñçóéìïðïéïýí áõôÝò ôéò êýñéåò äéáóôÜóåéò ãéá íá êáôáíïÞóïõí ôç
ãÝííçóç êáé ôï èÜíáôï ôïõ óýìðáíôïò. Ï êüóìïò óôïí ïðïßï æåßôå óÞìåñá
äçìéïõñãÞèçêå ìå ôï [1mBIG BANG [22mäéóåêáôïììýñéá ÷ñüíéá ðñéí (ó÷åäüí 20
äéóåêáôïììýñéá ÷ñüíéá ðñéí) ôï ïðïßï äçìéïõñãÞèçêå áðü
áëëçëåðéäñÜóåéò áôïìéêþí óùìáôéäßùí Üëëùí äéáóôÜóåùí. Ëßãï ðñéí ôï
big bang õðÞñ÷å Ýíá ðïëý ìéêñü óçìåßï üðïõ ôï ìÞêïò, ôï ðëÜôïò êáé ôï
ýøïò Þôáí ÌÇÄÅÍ (äçëáäÞ, ï êüóìïò ìáò äåí õðÞñ÷å åêåß!!) åíþ õðÞñ÷å ôï
õðüëïéðï óýìðáí êáé ïé êýñéåò äéáóôÜóåéò. Åêåßíç ôç ÷ñïíéêÞ óôéãìÞ äåí
õðÞñ÷áí Üôïìá, áóôÝñéá, ðëáíÞôåò êáé ãáëáîßåò! Ôá Üôïìá ìÝóá óôï óþìá
óáò äåí õðÞñ÷áí åêåß! ¸÷ïõí ãßíåé, ëïéðüí, ôüóá ðïëëÜ ðñÜãìáôá ÐÑÉÍ
íá ãåííçèåßôå!
Ôï Big bang êáé åðïìÝíùò êáé ç ãÝííçóç ôïõ êüóìïõ ìáò ðñïêëÞèçêå áðü
ëßãá Üôïìá êýñéùí äéáóôÜóåùí. [1mÊÁÐÏÉÏÓ [22m(êÜôé;) ðñïêÜëåóå ôç óõíôñéâÞ
åëÜ÷éóôùí ðïëý ìéêñþí áôüìùí Üëëùí äéáóôÜóåùí ìå áðïôÝëåóìá ôç
äçìéïõñãßá ôïõ êüóìïõ ìáò, êáé ãåííÞèçêáí íÝåò äéáóôÜóåéò ÷ñüíïõ,
ìÞêïõò, ðëÜôïõò, ýøïõò ! ÂëÝðïõìå ôï ÷Ýñé êÜðïéïõ óå áõôÞ ôç
äéáäéêáóßá. ÁõôÞ ç äéáäéêáóßá äåí åßíáé [1mêáé ðïëý êáôáíïçôÞ [22máðü ôïí
Üíèñùðï.
Ï Üíèñùðïò ðñïóðáèåß íá äçìéïõñãÞóåé Ýíáí Üëëï êüóìï óôï åñãáóôÞñéï
ðñïóïìïéþíïíôáò ôï ãåãïíüò big bang (âñßóêåôáé õðü êáôáóêåõÞ Ýíáò
ôåñÜóôéïò åðéôá÷õíôÞò óôçí Åõñþðç, Üëëç ìéá êáôáóêåõÞ óôï ÍôÜëáò, ç
ÁìåñéêÞ óôáìÜôçóå ëüãù ðåñéêïðþí óôïí ðñïûðïëïãéóìü). ÕðÜñ÷ïõí Üôïìá
Üëëùí äéáóôÜóåùí, üðùò Ý÷ïõìå êé åìåßò Üôïìá óôïí äéêü ìáò êüóìï.
ÈåùñçôéêÜ, ìðïñåßôå íá äçìéïõñãÞóåôå/ðáñÜãåôå Üðåéñï áñéèìü êüóìùí!
ÁõôÞ ç äéáäéêáóßá åßíáé áíôéóôñåðôÞ, äçëáäÞ ï êüóìïò ìáò ìðïñåß íá
óõññéêíùèåß óå ìåñéêÜ Üôïìá Üëëùí äéáóôÜóåùí! Åßíáé ðáñüìïéï ìå ôï íá
ãåííçèÞêáôå áðü äýï ìéêñïóêïðéêÝò êõøÝëåò ïé ïðïßåò èá óõãêñïõóôïýí
ãéá íá äçìéïõñãÞóïõí ìßá ìüíï êõøÝëç. ÁõôÞ ç ìüíç ìéêñïóêïðéêÞ
êõøåëßäá äéáéñÝèçêå êáé ðïëëáðëáóéÜóôçêå óå 6 ôñéóåêáôïììýñéá
êõøåëßäåò ìÝ÷ñé íá ãßíåé Ýíáò Üíèñùðïò ýøïõò 6 ðüäéá (äçëáäÞ åóåßò!).
ÕðÜñ÷ïõí ìåñéêÝò ïìïéüôçôåò ìåôáîý áíèñþðïõ êáé óýìðáíôïò, ôï óýìðáí
ãåííéÝôáé êáé áñãüôåñá ðåèáßíåé üðùò êáé ïé Üíèñùðïé. Ìéá êáé åßíáé
áäýíáôç ìéá ÔÅËÅÉÁ êáôÜóôáóç (üðùò êáé ç ÁÐÏËÕÔÙÓ ÌÇ ÔÅËÅÉÁ
êáôÜóôáóç), ïé êüóìïé óáí ôïõò äéêïýò ìáò ãåííéïýíôáé êáé ðåèáßíïõí
áñãüôåñá ìå ìéá êõêëéêÞ äéáäéêáóßá. ÁËËÁ äåí õðÜñ÷åé ÔÅËÅÉÏÓ èÜíáôïò,
ìüíï ìåôáó÷çìáôéóìüò åðéôñÝðåôáé áðü ôçí åðéóôÞìç! Ï êüóìïò ìáò
ìåãáëþíåé ìå ôá÷ýôáôï ñõèìü, äåí åßíáé óôáôéêüò, áíôßèåôá åßíáé ðïëý
äõíáìéêüò. Áõôüò ï êüóìïò èá óõíå÷ßóåé íá ìåãáëþíåé þóðïõ íá
ðáñåìâëçèåß êÜôé ðïõ èá êáôáóôñÝøåé ôïí êüóìï ìáò åöáñìüæïíôáò
äõíÜìåéò ìå åîùôåñéêÝò äéáóôÜóåéò ðïõ èá áðïññïöÞóïõí êáé èá
åîáöáíßóïõí ôïí êüóìï ìáò! ÕðÜñ÷ïõí äýï ðéèáíüôçôåò - íá áðïìáêñõíèåß
ç ìÜæá áðü ôïí êüóìï ìáò ìÝóù ôùí ìáýñùí ôñõðþí (áñãÞ äéáäéêáóßá), Þ
íá ðñïóôåèåß êáé Üëëç ìÜæá óôïí êüóìï ìáò ìÝóù ôùí Üóðñùí ôñõðþí
(ãñÞãïñç äéáäéêáóßá ìåãÜëçò óýãêñïõóçò). Ìðïñåß íá õðÜñ÷ïõí
åêáôïììýñéá êüóìïé áëëÜ ëßãïé åßíáé áõôïß ðïõ äçìéïõñãÞèçêáí áðü
êýñéåò äéáóôÜóåéò. Äåí Ý÷åôå öôéá÷ôåß ìüíï áðü Üôïìá áõôïý ôïõ êüóìïõ
áëëÜ êáé áðü Üôïìá Üëëùí äéáóôÜóåùí! Óôéò ìáýñåò ôñýðåò ôá Üôïìá êáé
ôá óùìáôßäéá ôïõ êüóìïõ ìáò ìÝíïõí åãêëùâéóìÝíá êáé ìåôáó÷çìáôßæïíôáé
êáé ìåôáôñÝðïíôáé ôåëåßùò óå óùìáôßäéá Üëëùí äéáóôÜóåùí! Óôï êÝíôñï
ìéáò ìáýñçò ôñýðáò ï ÷ñüíïò, ôï ðëÜôïò êáé ôï ýøïò åßíáé ìçäÝí! Êáé ç
ìáýñç ôñýðá åßíáé ç ðüñôá ÅÎÏÄÏÕ/ÅÉÓÏÄÏÕ ðñüò êáé áðü Üëëïõò êüóìïõò.
Ðüñôåò ÅÉÓÏÄÏÕ/ÅÎÏÄÏÕ ðñïò Üëëïõò êüóìïõò ìðïñïýí íá áíïßîïõí ðáíôïý,
áêüìç êáé ìÝóá óôï óþìá óáò! Ìðïñåß íá õðÜñ÷åé Üðåéñïò áñéèìüò
÷ñùìÜôùí, ãëùóóþí õðïëïãéóôÞ, ó÷åäßùí ôóéð õðïëïãéóôÞ êáé èåùñßåò áëëÜ
ÄÅÍ ÌÐÏÑÅÉ íá õðÜñîåé ÅÍÁ ÌÏÍÏ ÔÅËÅÉÏ ÷ñþìá, ãëþóóá õðïëïãéóôÞ, ó÷Ýäéï
Þ óýóôçìá! Áõôü ðïõ ìðïñåßôå íá Ý÷åôå åßíáé ìüíï Ýíá Ó×ÅÄÏÍ ÔÅËÅÉÏ
÷ñþìá (åýñïò êýìáôïò), óýóôçìá, âÜóç äåäïìÝíùí Þ èåùñßá! Ç öýóç åßíáé
üðùò Ýíá Êáëåéäïóêüðéï.
ÓõíäõÜæïíôáò ôçí åíÝñãåéá åêáôïììõñßùí áíèñþðùí óå üëï ôïí êüóìï ìÝóù
internet, åßíáé äõíáôü íá åðéôåõ÷èåß Ýíá [1mÓ×ÅÄÏÍ ÔÅËÅÉÏ [22móýóôçìá
(óõìðåñéëáìâáíïìÝíïõ åíüò óõóôÞìáôïò âÜóåùí äåäïìÝíùí). Ç åíÝñãåéá ôïõ
êÜèå áíèñþðïõ áôïìéêÜ åßíáé åëÜ÷éóôç, áëëÜ äéáóõíäÝïíôáò Ýíá ìåãÜëï
áñéèìü áíèñþðùí, ç óõíïëéêÞ åíÝñãåéá èá åßíáé ôåñÜóôéá ãéá íá
äçìéïõñãÞóåé Ýíá ó÷åäüí ôÝëåéï óýóôçìá. Ïé Üíèñùðïé åßíáé üíôá ìå
ðåñéïñéóìÝíç åíÝñãåéá êáé áðïèÝìáôá, êáé ðïëý óõ÷íÜ óå áõôïýò
ïöåßëïíôáé ëÜèç áðü áðëÜ ìÝ÷ñé êáé ðïëý óïâáñÜ. ÅðåéäÞ ç ôÜóç ìáò ãéá
ëÜèç ðïéêßëëåé óå êÜèå Üíèñùðï áíÜëïãá ìå ôéò éäéáßôåñåò
åðéäåîéüôçôåò, ôç óõãêåêñéìÝíç åìðåéñßá ðïõ Ý÷åé ï êáèÝíáò êáé ôéò
óõãêõñßåò ôçò óõãêåêñéìÝíçò óôéãìÞò, ç áíáêÜëõøç êáé ç åëÜôôùóç ôùí
ëáèþí ëïãéóìéêïý (bugs) ðïõ äçìéïõñãïýíôáé áðü êÜðïéï Üíèñùðï
äéåõêïëýíåôáé ìå ôç óõãêÝíôñùóç ðïëëþí Ýîõðíùí áíèñþðùí-ìõáëþí ãéá íá
áíôéìåôùðßóïõí ôï óõãêåêñéìÝíï ðñüâëçìá. Ðåñéóóüôåñá Üôïìá
óõíåðÜãåôáé ðåñéóóüôåñåò áíèñùðïþñåò ãéá êþäéêá êáé ôçí áíôßóôïé÷ç
ëåéôïõñãßá ôïõ.
Åßíáé îåêÜèáñï üôé ôï ßíôåñíåô ìðïñåß íá äéáóõíäÝóåé Ýíá ôåñÜóôéï
áñéèìü áíèñþðùí, üðïõ üëïé ìáæß äéáèÝôïõí ðïëý åíÝñãåéá êáé ÷ñüíï. Ìå
ôï óõíäõáóìü ôïõò ìðïñïýí íá ðáñá÷èïýí ðñïúüíôá ëïãéóìéêïý õøçëüôåñçò
ðïéüôçôáò óå ðïëý ëéãüôåñï ÷ñüíï óå óýãêñéóç ìå åìðïñéêÝò åôáéñåßåò.
Áêüìç êáé ìåãÜëåò åôáéñåßåò üðùò ç Microsoft, ç IBM äå ìðïñïýí íá
õðåñéó÷ýóïõí êáé íá áãíïÞóïõí ôïõò íüìïõò ôçò ÖõóéêÞò áëëÜ èá
[1mÕÐÏÔÁ×ÈÏÕÍ [22môåëéêÜ óå áõôïýò!
ÓÞìåñá, õðÜñ÷ïõí ôüóåò ðïëëÝò âÜóåéò äåäïìÝíùí óå üëï ôïí êüóìï ðïõ
óôï÷åýïõí ìüíï óôéò ðñïäéáãñáöÝò ANSI/ISO SQL. [1mÏé Üíèñùðïé äåí ðñÝðåé[0m
[1míá ÷áñáìßæïõí ôï ÷ñüíï ôïõò ãéá íá äçìéïõñãÞóïõí ôüóá ðïëëÜ[0m
[1mÐÁÑÏÌÏÉÁ/ÏËÏÉÄÉÁ ðáêÝôá ëïãéóìéêïý [22måíþ õðÜñ÷ïõí ôüóïé Üëëïé ôïìåßò
ôçò åðéóôÞìçò ðïõ ÷ñåéÜæïíôáé ðñïóï÷Þ. Ôï óõìðÝñáóìá åßíáé ôï åîÞò :
åîáéôßáò ôùí íüìùí ôçò åðéóôÞìçò, ôá 'áíïé÷ôÜ óõóôÞìáôá ðçãáßïõ
êþäéêá' üðùò ç PostgreSQL, ôï Linux èá åßíáé ðÜíôá ðïëý êáëýôåñá áðü
ôá 'êëåéóôÜ óõóôÞìáôá ðçãáßïõ êþäéêá' êáé áõôü åßíáé äõíáôü íá
áðïäåé÷ôåß êáé åðéóôçìïíéêÜ.
[1m4. Ôé åßíáé ç PostgreSQL ;[0m
Ç PostgreSQL Ýêäïóç 6.4 åßíáé ìéá äùñåÜí âÜóç, ìå ôçí ïðïßá óáò
äßíåôáé üëïò ï ðçãáßïò êþäéêáò êáé åßíáé Ýíá Óýóôçìá
ÁíôéêåéìåíïóôñáöÞò-Ó÷åóéáêÞ ÂÜóçò ÄåäïìÝíùí ó÷åäüí óõìâáôÞ ìå
(ðëçóéÜæåé üëï êáé ðåñéóóüôåñï) ìå ôï ANSI SQL1998,92,89 êáé ôñÝ÷åé óå
äéáöïñåôéêÝò ðëáôöüñìåò hardware êáé ËåéôïõñãéêÜ óõóôÞìáôá.
ÌåñéêÝò öïñÝò âãáßíïõí óå êõêëïöïñßá Ýêôáêôåò äéïñèþóåéò, ìðáëþìáôá (patches) ãéá äéïñèþóåéò
ëáèþí ìåôÜ ôçí Ýêäïóç GA PostgreSQL. Ìðïñåßôå íá åöáñìüóåôå ôá ðñïáéñåôéêÜ patches
áíÜëïãá ìå ôéò áíÜãêåò ôçò åöáñìïãÞò óáò. ÁêïëïõèÞóôå ôá ðáñáêÜôù
âÞìáôá ãéá íá åöáñìüóåôå ôá patches -
Ðçãáßíåôå óôïí êáôÜëïãï ðïõ âñßóêåôáé ï êþäéêáò ôçò postgresql
cd /usr/src/postgresql6.3.1
patch -p0 < patchfile
make clean
make
Äåßôå åðßóçò ôç óåëßäá âïÞèåéáò ãñÜöïíôáò 'man patch'
Ôá áñ÷åßá ãéá patch âñßóêïíôáé óôï
· PostgreSQL patches : <ftp://ftp.postgresql.org/pub/patches>
Ï áðüëõôïò óêïðüò êáé ï ôåëéêüò óôü÷ïò ôçò PostgreSQL åßíáé ãßíåé 100
% óõìâáôÞ ìå ôçí ANSI/ISO SQL êáé íá ãßíåé åðßóçò ç íïýìåñï ÅÍÁ
ÁíïéêôÞ ÃåíéêÞ ÂÜóç óôïí êüóìï. Ç PostgreSQL åðßóçò èá ïäçãÞóåé,
äéåõèýíåé, åëÝãîåé, ðáñáêïëïõèÞóåé êáé õðáãïñåýóåé ôï ìÝëëïí ôçò
ANSI/ISO SQL. Áõôü ãéáôß, ç õëïðïßçóç êáé ïé éäÝåò ãßíïíôáé ðñþôá
óôçí PostgreSQL êáé Ýðåéôá åíóùìáôþíïíôáé óôçí ANSI/ISO SQL.
Ï Informix Universal server (åêäüèçêå ôï 1997) âáóßæåôáé óå
ðñïçãïýìåíç Ýêäïóç ôçò PostgreSQL åðåéäÞ ç Informix áãüñáóå ôçí
Illustra Inc. êáé åíïðïéÞèçêå ìå ôçí Informix. Ç âÜóç Illustra Þôáí
ðëÞñùò âáóéóìÝíç óôçí Postgres (ðñïçãïýìåíç Ýêäïóç ôçò PostgreSQL).
Ç PostgreSQL åßíáé ìéá åðÝêôáóç ôïõ óõóôÞìáôïò äéá÷åßñéóçò ôçò âÜóçò
äåäïìÝíùí POSTGRES, Ýíá åðüìåíçò ãåíéÜò ðñüôõðï Ýñåõíáò DBMS. Åíþ ç
PostgreSQL äéáôçñåß ôï äõíáìéêü ìïíôÝëï äåäïìÝíùí êáé ôïõò ðëïýóéïõò
ôýðïõò äåäïìÝíùí ôçò POSTGRES, áíôéêáèéóôÜ ôçí ãëþóóá åñùôÞóåùí
PostQuel ìå Ýíá åêôåôáìÝíï õðïóýíïëï ôçò SQL.
Ç áíÜðôõîç ôçò PostgreSQL ãßíåôáé áðü ìéá ïìÜäá ðñïãñáììáôéóôþí óôï
Internet ðïõ åßíáé üëïé ãñáììÝíïé óôç ëßóôá áëëçëïãñáößáò áíÜðôõîçò
ôçò PostgreSQL. ÓõíôïíéóôÞò ôçò ïìÜäáò åßíáé ï Marc G. Fournier
· scrappy@postgreSQL.org
ÁõôÞ ç ïìÜäá åßíáé õðåýèõíç ãéá üëç ôçí ôñÝ÷ïõóá êáé ìåëëïíôéêÞ
áíÜðôõîç ôçò PostgreSQL. ÖõóéêÜ, ï ßäéïò ï ðåëÜôçò âÜóåùí
äåäïìÝíùí åßíáé áõôüò ðïõ áíáðôýóóåé ôçí PostgreSQL! Ôï öïñôßï ôçò
áíÜðôõîçò äéáíÝìåôáé óå Ýíá ðïëý ìåãÜëï áñéèìü ôåëéêþí ÷ñçóôþí
âÜóåùí óôï internet.
Ïé óõããñáöåßò ôçò PostgreSQL 1.01 åßíáé ïé Andrew Yu êáé Jolly Chen.
Ðïëëïß Üëëïé óõíåéóÝöåñáí óå áõôÞ ôç ìåôáöïñÜ, ôï ôåóôÜñéóìá, ôçí
áðïóöáëìÜôùóç êáé ôçí åðÝêôáóç ôïõ êþäéêá. Ï áñ÷éêüò êþäéêáò ôçò
Postgres, áð' üðïõ ðñïÝêõøå ç PostgreSQL, Þôáí ç ðñïóðÜèåéá ðïëëþí
áðïöïßôùí óðïõäáóôþí, ìåôáðôõ÷éáêþí, êáé ðñïóùðéêïý ðñïãñáììáôéóôþí
ðïõ äïýëåøáí êÜôù áðü ôçí åðßâëåøç ôïõ ÊáèçãçôÞ Michael Stonebraker
óôï ÐáíåðéóôÞìéï ôçò Êáëéöüñíéá, óôï Berkeley.
Ôï áñ÷éêü üíïìá ôïõ ëïãéóìéêïý óôï Berkeley Þôáí Postgres. ¼ôáí
ðñïóôÝèçêå ç ëåéôïõñãéêüôçôá ãéá SQL ôï 1995, ôï üíïìá Üëëáîå óå
Postgres95. Ôï üíïìá Üëëáîå ðÜëé óôï ôÝëïò ôïõ 1996 óå PostgreSQL.
Åêáôïììýñéá PostgreSQL Ý÷ïõí åãêáôáóôáèåß ùò äéáêïìéóôÝò âÜóåùí
äåäïìÝíùí, Web database serversêáé Application data servers. Åßíáé
ðïëý ðñï÷ùñçìÝíç, êáé åßíáé áíôéêåéìåíïóôñáöÞò ó÷åóéáêÞ âÜóç
äåäïìÝíùí (ORDBMS).
H PostgreSQL ìðïñåß íá áðïèçêåýóåé ðåñéóóüôåñïõò ôýðïõò äåäïìÝíùí áðü
ôïõò ðáñáäïóéáêïýò ôýðïõò äåäïìÝíùí üðùò integer, characters, êëð. -
ìðïñåßôå íá äçìéïõñãÞóåôå ôïõò äéêïýò óáò ïñéóìÝíïõò ôýðïõò,
óõíáñôÞóåéò, êëçñïíïìéêüôçôá êëð. Ç PostgreSQL ôñÝ÷åé óå Solaris,
SunOS, HPUX, AIX, Linux, Irix, Digital Unix, BSDi,NetBSD, FreeBSD, SCO
unix, NEXTSTEP, Unixware êáé óå ïðïéïäÞðïôå ôýðï Unix. Ç ìåôáöïñÜ ôçò
óå Windows 95/NT åßíáé óå åîÝëéîç.
· Ôßôëïò: PostgreSQL SQL RDBMS Database (Óýóôçìá
Äéá÷åßñéóçò Áíôéêåéìåíïóôñáöïýò Ó÷åóéáêÞò ÂÜóçò ÄåäïìÝíùí)
· ÔñÝ÷ïõóá Ýêäïóç: 6.4
· ×ñïíïëïãßá: Ç PostgreSQL åßíáé 12 ÷ñïíþí. Áíáðôýóóåôáé áðü ôï
1985
· Óõããñáöåßò: Áíáðôýóóåôáé áðü
åêáôïììýñéá/ðáíåðéóôÞìéá/åôáéñåßåò óôï internet ãéá ôá ôåëåõôáßá 12
÷ñüíéá
Ç PostgreSQL êáé ôá ó÷åôéêÜ êïììÜôéá ôïõ êåéìÝíïõ õðüêåéíôáé óôçí
ðáñáêÜôù ÐÍÅÕÌÁÔÉÊÇ ÉÄÉÏÊÔÇÓÉÁ.
PostgreSQL Óýóôçìá Äéá÷åßñéóçò ÂÜóçò ÄåäïìÝíùí
ÐíåõìáôéêÞ Éäéïêôçóßá (c) ôïõ ðáíåðéóôçìßïõ ôçò California
¶äåéá ãéá ÷ñÞóç, áíôéãñáöÞ, ìåôáâïëÞ, êáé äéáíïìÞ áõôïý ôïõ ëïãéóìéêü êáé ôçò
ôåêìçñßùóÞò ôïõ ãéá ïðïéïäÞðïôå óêïðü, ÷ùñßò ôÝëç, êáé ÷ùñßò ãñáðôÞ óõìöùíßá
ðáñÝ÷åôáé, ìå ôçí ðñïûðüèåóç üôé ôï óçìåßùìá ðíåõìáôéêÞò éäéïêôçóßáò êáé
áõôÞ êáé ïé ðáñáêÜôù äýï ðáñÜãñáöïé èá åìöáíßæïíôáé óå üëåò ôéò êüðéåò.
ÌÅ ÊÁÍÅÍÁÍ ÔÑÏÐÏ, ÄÅÍ ÈÁ ÈÅÙÑÇÈÅÉ ÔÏ ÐÁÍÅÐÉÓÔÇÌÉÏ ÔÇÓ ÊÁËÉÖÏÑÍÉÁ ÍÏÌÉÊÁ ÕÐÅÕÈÕÍÏ
ÃÉÁ ÁÌÅÓÇ, ÅÌÌÅÓÇ, ÅÉÄÉÊÇ, ÔÕ×ÁÉÁ, Ç ÐÁÑÁÃÙÌÅÍÇ ÆÇÌÉÁ, ÓÕÌÐÅÑÉËÁÌÁÍÏÌÅÍÇÓ ÊÁÉ ÔÇÓ
ÁÐÙËÅÉÁÓ ÊÅÑÄÙÍ ÐÏÕ ÐÑÏÅÊÕØÅ ÁÐÏ ÔÇÍ ×ÑÇÓÇ ÁÕÔÏÕ ÔÏÕ ËÏÃÉÓÌÉÊÏÕ ÊÁÉ ÔÇÓ
ÔÅÊÌÇÑÉÙÓÇÓ ÔÏÕ, ÁÊÏÌÁ ÊÁÉ ÁÍ ÔÏ ÐÁÍÅÐÉÓÔÇÌÉÏ ÔÇÓ ÊÁËÉÖÏÍÉÁ Å×ÅÉ ÅÉÄÏÐÏÉÇÈÅÉ ÃÉÁ
ÔÇÍ ÐÉÈÁÍÏÔÇÔÁ ÌÉÁÓ ÔÅÔÏÉÁÓ ÆÇÌÉÁÓ.
ÔÏ ÐÁÍÅÐÉÓÔÇÌÉÏ ÔÇÓ ÊÁËÉÖÏÑÍÉÁ ÅÉÄÉÊÁ ÁÐÁÑÍÅÉÔÁÉ ÊÁÈÅ ÅÃÃÕÓÇÓÇ, ÓÕÌÐÅÑÉËÁÌÂÁÍÏÌÅÍÇÓ,
ÁËËÁ Ï×É ÐÅÑÉÏÑÉÓÌÅÍÇÓ ÌÏÍÏ ÓÅ ÁÕÔÇÍ, ÔÇÓ ÕÐÏÍÏÏÕÌÅÍÇÓ ÅÃÃÕÇÓÇÓ ×ÑÇÓÇÓ, ÊÁÉ ×ÑÇÓÇÓ
ÃÉÁ ÊÁÐÏÉÏ ÓÕÃÊÅÊÑÉÌÅÍÏ ÓÊÏÐÏ. ÔÏ ËÏÃÉÓÌÉÊÏ ÐÏÕ ÐÁÑÅ×ÅÔÁÉ ÅÄÙ ÅÉÍÁÉ ÓÅ ÂÁÓÇ "ÙÓ Å×ÅÉ"
ÊÁÉ ÔÏ ÐÁÍÅÐÉÓÔÇÌÉÏ ÔÇÓ ÊÁËÉÖÏÑÍÉÁÓ ÄÅÍ Å×ÅÉ ÕÐÏ×ÑÅÙÓÇ ÃÉÁ ÐÁÑÏ×Ç ÓÕÍÔÇÑÇÓÇÓ, ÅÍÇÌÅÑÙÓÅÙÍ,
ÅÌÐËÏÕÔÉÓÌÙÍ, Ç ÔÑÏÐÏÐÏÉÇÓÅÙÍ.
[1m5. Ðïý ìðïñþ íá ôç âñù ;[0m
Ìðïñåßôå íá áãïñÜóåôå ôï CDROM Redhat Linux, Debian Linux Þ ôï
Slackware Linux ðïõ ðåñéÝ÷ïõí Þäç ôçí Postgresql óå ìïñöÞ ðáêÝôïõ (êáé
ï ðçãáßïò êþäéêáò êáé ôá åêôåëÝóéìá) áðü ôá :
· Linux System Labs Web site: <http://www.lsl.com/> 7 (U.S.
äïëÜñéá)
· Cheap Bytes Inc Web site: <http://www.cheapbytes.com/> 7 (U.S.
äïëÜñéá)
· Debian Êåíôñéêü Web site : <http://www.debian.org/vendors.html>
Ï ïñãáíéóìüò PostgreSQL ðïõëÜ åðßóçò Ýíá 'PostgreSQL CDROM' ðïõ
ðåñéÝ÷åé üëïí ôïí ðçãáßï êþäéêá êáé åêôåëÝóéìá ãéá ðïëëÜ ëåéôïõñãéêÜ
óõóôÞìáôá Unix êáé ðëÞñç ôåêìçñßùóç.
· Ôï CDROM ôçò PostgreSQL èá ôï âñåßôå áðü ôï êåíôñéêü Web site ôçò
óôï : <http://www.postgresql.org> ãéá 29 (ÁìåñéêÜíéêá äïëÜñéá)
ÄéáíïìÞ ôçò PostgreSQL ìüíï ìå åêôåëÝóéìá:
· Ìðïñåßôå íá ôñÝîåôå ôçí PostgreSQL ÷ùñßò íá ìåôáãëùôôßóåôå ôïí
êþäéêá. ÅãêáôáóôÞóôå ôá åêôåëÝóéìá ãéá Intel-Linux áðü ôï áñ÷åßï
<ftp://www.redhat.com/pub/contrib/i386/> postgresql-6.4.i386.rpm.
Áõôü åßíáé Ýíá redhat 'rpm' ðáêÝôï êáé ðåñéÝ÷åé êáé ôïí êþäéêá êáé
ôá åêôåëÝóéìá ãéá ôçí PostgreSQL.
· Site ìå åêôåëÝóéìá ãéá Solaris, HPUX, AIX, IRIX, Linux :
<ftp://ftp.postgresql.org/pub/bindist> Áí ìåôáãëùôôßóåôå ôïí êþäéêá
ãéá ïðïéáäÞðïôå ðëáôöüñìá, ðáñáêáëþ óôåßëôå ôï óôï site, ìðïñåß íá
åßíáé ÷ñÞóéìï ãéá ôïõò õðüëïéðïõò.
· ftp site : ÐÜñôå ôá åêôåëÝóéìá ãéá Intel-Linux áðü ôï áñ÷åßï
<ftp://ftp.redhat.com/pub/contrib/i386/> postgresql-6.4.i386.rpm.
Áõôü åßíáé Ýíá redhat 'rpm' ðáêÝôï êáé ðåñéÝ÷åé êáé ôïí êþäéêá êáé
ôá åêôåëÝóéìá ãéá ôçí PostgreSQL.
WWW Web sites:
· Êåíôñéêü Web site: <http://www.postgresql.org/>
· Äåýôåñï Web site: <http://logical.thought.net/postgres95/>
· <http://www.itm.tu-clausthal.de/mirrors/postgres95/>
· <http://s2k-ftp.cs.berkeley.edu:8000/postgres95/>
· <http://xenium.pdi.net/PostgreSQL/>
· <http://s2k-ftp.cs.berkeley.edu:8000/postgres95/>
Ôá ftp sites ðáñïõóéÜæïíôáé ðáñáêÜôù :-
· Primary FTP: <ftp://ftp.postgresql.org/pub>
· Secondary FTP: <ftp://ftp.chicks.net/pub/postgresql>
· <ftp://ftp.emsi.priv.at/pub/postgres/>
· <ftp://ftp.itm.tu-clausthal.de/pub/mirrors/postgres95>
· <ftp://rocker.sch.bme.hu/pub/mirrors/postgreSQL>
· <ftp://ftp.jaist.ac.jp/pub/dbms/postgres95>
· <ftp://ftp.luga.or.at/pub/postgres95>
· <ftp://postgres95.vnet.net:/pub/postgres95>
· <ftp://ftpza.co.za/mirrors/postgres>
· <ftp://sunsite.auc.dk/pub/databases/postgresql>
· <ftp://ftp.task.gda.pl/pub/software/postgresql>
· <ftp://xenium.pdi.net/pub/PostgreSQL>
Ï ðçãáßïò êþäéêáò ôçò PostgreSQL åßíáé åðßóçò äéáèÝóéìïò óå üëá ôá
mirror sites ôïõ sunsite unc (óýíïëï ðåñßðïõ 1000 sites óå üëï ôïí
êüóìï). Âñßóêåôáé åðßóçò óôç äéáíïìÞ ôïõ Red Hat Linux óôï áñ÷åßï
/pub/contrib/i386/postgresql.rpm .
· Ãéá ôç ëßóôá ôùí mirror sites ðçãáßíåôå óôï
<ftp://sunsite.unc.edu>
[1m6. Ç PostgreSQL õðïóôçñßæåé åîáéñåôéêÜ ìåãÜëåò âÜóåéò, ìåãáëýôåñåò[0m
[1máðü 200 Gig[0m
Ç áðüäïóç ôùí 32-bit ìç÷áíþí cpu èá ðÝóåé ãñÞãïñá üôáí ôï ìÝãåèïò ôçò
âÜóçò îåðåñÜóåé ôá 5 gig. Ìðïñåßôå íá ôñÝîåôå âÜóç ôùí 30 gig óå ìéá
32-bit cpu áëëÜ ç áðüäïóç äå èá åßíáé êáé ðïëý åíôõðùóéáêÞ. ÕðÜñ÷ïõí
ðåñéïñéóìïß ðïõ åðéâÜëëïíôáé áðü ôï ìÝãåèïò ôçò ìíÞìçò RAM (ìÝãéóôï 2
gig ìüíï), ðåñéïñéóìïß áðü ôá ìåãÝèç ôïõ óõóôÞìáôïò áñ÷åßùí êáé åðßóçò
áðü ôï ëåéôïõñãéêü óýóôçìá.
Áí ÷ñåéÜæåôáé íá ÷ñçóéìïðïéÞóåôå åîáéñåôéêÜ ìåãÜëåò âÜóåéò, óáò
óõìâïõëåýïõìå íá ÷ñçóéìïðïéÞóåôå ìç÷áíÝò ôùí 64-bit üðùò Digital Alpha
cpu, Sun Ultra-sparc 64-bit cpu, Silicon graphics 64-bit cpu, Intel
Merced IA-64 cpu, ìç÷áíÝò HPUX 64bit, IBM 64-bit. Ìåôáãëùôôßóôå ôçí
PostgreSQL óå ìéá 64-bit cpu êáé èá ìðïñåß íá õðïóôçñßæåé ôåñÜóôéåò
âÜóåéò êáé ìåãÜëá queries. Ç áðüäïóç ôçò PostgreSQL ãéá åñùôÞóåéò óå
ìåãÜëïõò ðßíáêåò êáé âÜóåéò èá åßíáé ðïëëÝò öïñÝò ôá÷ýôåñç áðü ôçí
PostgreSQL óå ìç÷áíÝò ìå cpu 32-bit. Ôï ðëåïíÝêôçìá ôùí ìç÷áíþí 64-bit
åßíáé üôé ç äåéêôïäüôçóç ôïõ ÷þñïõ ìíÞìçò åßíáé ðïëý ìåãÜëç êáé ôï
ëåéôïõñãéêü óýóôçìá ìðïñåß íá õðïóôçñßîåé óõóôÞìáôá ìåãÜëùí áñ÷åßùí,
ðáñÝ÷åé êáëýôåñç áðüäïóç ìå ìåãÜëåò âÜóåéò, õðïóôçñßæåé ðïëý
ðåñéóóüôåñç ìíÞìç (RAM), Ý÷ïõí ðåñéóóüôåñåò äõíáôüôçôåò êëð.
[1m7. áíáðôýóóåé ôï áßóèçìá åìðéóôïóýíçò óôïí ðåëÜôç Ðþò ìðïñþ íá[0m
[1måìðéóôåõèþ ôçí PostgreSQL ; Ôï ðáêÝôï Regression ãéá ôåóô[0m
Ôï ðáêÝôï Regression ãéá ôåóô (src/test/regress) ðåñéëáìâÜíåôáé óôç
äéáíïìÞ êáé áöÞóôå ôïí õðïëïãéóôÞ óáò íá åðáëçèåýóåé ôéò óôÜíôáñ
ëåéôïõñãßåò SQL êáé ôéò äõíáôüôçôåò åðÝêôáóçò ôçò PostgreSQL. Ôï
ðáêÝôï ãéá ôåóô ðåñéÝ÷åé Þäç åêáôïíôÜäåò SQL ôåóô ðñïãñÜììáôá.
Èá ðñÝðåé íá ÷ñçóéìïðïéÞóåôå ôç äýíáìç ôïõ õðïëïãéóôÞ ãéá íá åëÝãîåôå
ôçí PostgreSQL, áíôß íá ÷ñçóéìïðïéÞóåôå ôç äýíáìç ôïõ áíèñþðéíïõ
åãêåöÜëïõ. Ïé õðïëïãéóôÝò ìðïñïýí íá åêôåëÝóïõí ôåóô ãéá ôï ëïãéóìéêü
regression åêáôïììýñéá Þ áêüìç êáé äéóåêáôïììýñéá öïñÝò ãñçãïñüôåñá
áðü üôé ïé Üíèñùðïé.
Óôï ðñïóå÷Ýò ìÝëëïí ç ôá÷ýôçôá ôùí õðïëïãéóôþí èá åßíáé áñêåôÜ
ôñéóåêáôïììýñéá öïñÝò ãñçãïñüôåñïé áðü ôïí áíèñþðéíï åãêÝöáëï!
¸ôóé, Ý÷åé íüçìá íá ÷ñçóéìïðïéÞóïõìå ôç äýíáìç ôïõ õðïëïãéóôÞ ãéá íá
åëÝã÷ïõìå ëïãéóìéêü.
Ìðïñåßôå íá ðñïóèÝóåôå êáé Üëëá ôåóô óå ðåñßðôùóç ðïõ ôï ÷ñåéÜæåóôå,
êáé ìðïñåßôå íá ôá óôåßëåôå óôï êåíôñéêü web site ôçò PostgreSQL áí
íïìßæåôå üôé èá åßíáé ÷ñÞóéìï óå Üëëïõò óôï internet. Ôï ðáêÝôï
Regression ãéá ôåóô åíéó÷ýåé ôçí åìðéóôïóýíç ôïõ ðåëÜôç óôçí
PostgreSQL êáé åõêïëýíåé ôç ãñÞãïñç åöáñìïãÞ ôçò PostgreSQL óå
óõóôÞìáôá ðáñáãùãÞò.
Ôï ðáêÝôï Regression ãéá ôåóô ìðïñåß íá èåùñçèåß óáí Ýíá [1m"ÐÏËÕ[0m
[1mÓÔÁÈÅÑÏ" [22môå÷íéêü êåßìåíï óõìöùíçìÝíï áìïéâáßá ìåôáîý ôùí
ðñïãñáììáôéóôþí êáé ôùí ôåëéêþí ÷ñçóôþí. Ïé ðñïãñáììáôéóôÝò ôçò
PostgreSQL ÷ñçóéìïðïéïýí åêôåôáìÝíá ôï ðáêÝôï regression ãéá ôåóô êáôÜ
ôçí ðåñßïäï ôçò áíÜðôõîçò êáé åðßóçò ðñéí ôçí Ýêäïóç ôïõ ëïãéóìéêïý
óôï êïéíü ãéá íá äéáóöáëßóïõí ôçí êáëÞ ðïéüôçôá.
Ïé äõíáôüôçôåò ôçò PostgreSQL áíôéêáôñïðôßæïíôáé óôï ðáêÝôï ãéá ôåóô
regression. Óå ðåñßðôùóç ðïõ ìéá äõíáôüôçôá, óýíôáîç Þ ÷áñáêôçñéóôéêü
äåí ðåñéëáìâÜíåôáé óôï ðáêÝôï äåí óçìáßíåé ðùò êáëýðôåôáé áíáãêáóôéêÜ
áðü ôçí PostgreSQL. Ìðïñåßôå íá ôï åëÝãîåôå, ðáñüëá áõôÜ, åóåßò êáé íá
åíóùìáôþóåôå ôï ôåóô óáò óôï ðáêÝôï.
[1m8. Ãñáöéêü ðñüãñáììá åðéêïéíùíßáò (GUI FrontEnd Tool) ìå ôçí Post-[0m
[1mgreSQL[0m
Ç äéáíïìÞ ôçò PostgreSQL ðåñéëáìâÜíåé ìéá âéâëéïèÞêç óå Tcl/Tk, ðïõ
ïíïìÜæåôáé 'pgTcl'. Ç Tcl/Tk åßíáé Ýíá åñãáëåßï ãéá ãñÞãïñç áíÜðôõîç
åöáñìïãþí êáé ìéá ðïëý äõíáôÞ scripting ãëþóóá. Áíáðôýóóåôå ìéá öïñÜ
ôçí åöáñìïãÞ óáò êáé ôçí ôñÝ÷åôå ðáíôïý : óå NT, Win 95, Linux, OS/2
êáé üëá ôá óõóôÞìáôá unix. Tcl åßíáé ôá áñ÷éêÜ ôïõ 'Tool Command
Language' êáé Tk ôïõ 'Tool Kit'. ÕðÜñ÷åé Ýíá ïëïêëçñùìÝíï ðåñéâÜëëïí
áíÜðôõîçò (IDE - integrated development environment) ãéá ôçí Tcl/Tk
ðïõ ëÝãåôáé SpecTcl. ÊïéôÜîôå ãé áõôü ôï rpm ðáêÝôï óôç äéáíïìÞ Redhat
linux Þ óôï sunscript site ðïõ äßíåôáé ðáñáêÜôù.
Óõíéóôïýìå ôçí Perl ãéá ãëþóóá ðñïãñáììáôéóìïý ìéá êáé åßíáé ç ðéï
äéáäåäïìÝíç ãëþóóá, ðïëý éó÷õñÞ êáé äéáôßèåôáé ãéá üëá ôá ìç÷áíÞìáôá
êáé üëåò ôéò ðëáôöüñìåò ëåéôïõñãéêþí. Óáò óõìâïõëåýïõìå íá
÷ñçóéìïðïéÞóåôå Perl-Tk Þ Perl-Qt Þ C++ QtEZ Þ C++ Lesstiff. Ï
óõíäõáóìüò Perl, C êáé Tk èá éêáíïðïéÞóåé ôéò áíÜãêåò ôùí ðåñéóóïôÝñùí
projects, ëáìâÜíïíôáò õðüøç ôï äéáèÝóéìï ÷ñüíï, ôçí ôá÷ýôçôá ôùí
åêôåëÝóéìùí êáé ôçí åõêïëßá ðñïãñáììáôéóìïý. Óçìåéþóôå üôé ôá
ðñïãñÜììáôá óå Java ôñÝ÷ïõí ðïëý áñãÜ. Áêüìç êáé ôá ðñïãñÜììáôá ðïõ
åßíáé ãñáììÝíá óå C++ ôñÝ÷ïõí ðéï áñãÜ áðü ôá ðñïãñÜììáôá ðïõ
ãñÜöïíôáé óå C. Ôá ðñïãñÜììáôá óå C åêôåëïýíôáé ôá÷ýôåñá áðü ôá
áíôßóôïé÷á ðñïãñÜììáôá ãñáììÝíá óå ïðïéáäÞðïôå Üëëç ãëþóóá
ðñïãñáììáôéóìïý.
Ç Perl ÷ñçóéìïðïéåßôáé ãéá ôïí ðñïãñáììáôéóìü ôïõ 90 % ôùí internet
scripts óôïí êüóìï. ¸ôóé èá Ý÷åôå ìüíï ìéá ãëþóóá, ôçí "Perl", ãéá
üëåò óáò ôéò áíÜãêåò, óå åöáñìïãÝò üóï êáé óôï internet. Äåßôå ôï
Perl Database Interface áõôïý ôïõ êåéìÝíïõ óôï ``''
Èá ðñÝðåé íá ìåëåôÞóåôå ôá äõíáôÜ óçìåßá ôçò Perl óå óýãêñéóç ìå ôçí
Tcl/Tk ðñéí îåêéíÞóåôå êÜðïéï project óå Tcl. Ç Tcl/TK äßíåôáé
óõíÞèùò ìå êÜèå linux cdrom. Ìðïñåßôå åðßóçò íá ôç âñåßôå óôá sites -
· Tcl/Tk <http://www.scriptics.com>
· ÁíôéêåéìåíïóôñáöÝò extension ôçò Tcl ðïõ ïíïìÜæåôáé INCR óôï
<http://www.tcltk.com>
· Visual TCL site <http://www.neuron.com>
· Visual TCL Redhat rpm óôï
<ftp://ftp.redhat.com/pub/contrib/i386/visualtcl*.rpm>
· <http://sunscript.sun.com/>
· <http://sunscript.sun.com/TclTkCore/>
· <ftp://ftp.sunlabs.com/pub/tcl/tcl8.0a2.tar.Z>
· Âéâëßá áíáöïñþí: ÐïëëÜ ôå÷íéêÜ âéâëßá ãéá TCL/TK äéáôßèåíôáé óôçí
áãïñÜ.
[1m9. Åñãáëåßá åíüò ÏëïêëçñùìÝíïõ ÓõóôÞìáôïò ÁíÜðôõîçò ãéá PostgreSQL[0m
[1m(GUI IDE)[0m
ÊïéôÜîôå ôá ðáñáêÜôù åñãáëåßá áíÜðôõîçò ôá ïðïßá ìðïñåßôå íá
÷ñçóéìïðïéÞóåôå óå óõíäõáóìü ìå ïäçãïýò ODBC/JDBC. Áõôïß åßíáé
ðáñüìïéïé ìå Borland C++ Builder, Borland JBuilder.
Ôï Vibe åßíáé Java êáé C++ IDE (Integrated Development Environment)
êáé êÝñäéóå óôçí Unix Åðéóêüðçóç ãéá ôá ïëïêëçñùìÝíá óõóôÞìáôá
áíÜðôõîçò ôçò ÷ñïíéÜò.
· Ðåñéóóüôåñåò ðëçñïöïñßåò ãéá ôï Vibe óôï
<http://www.LinuxMall.com/products/00487.html>
· Ôï 'QT' åßíáé ìéá ðëáôöüñìá áíÜðôõîçò åöáñìïãþí ãéá Windows95/NT
êáé Unix <http://www.troll.no> êáé ôï ftp site ôïõ åßíáé ôï
<ftp://ftp.troll.no>
Ìðïñåßôå åðßóçò íá ÷ñçóéìïðïéÞóåôå Borland C++ Builder, Delphi,
Borland JBuilder, PowerBuilder óå Windows95 êáé íá óõíäåèåßôå ìå
ôçí PostgreSQL óå Ýíá óýóôçìá unix ìÝóù ïäçãþí ODBC/JDBC.
Äåßôå åðßóçò ôï [1mPERL [22mDatabase Interface óå áõôü ôï êåßìåíï óôï ``'' Ç
Perl êáé C/C++ óõíßóôáíôáé Ýíôïíá óáí åðéëïãÝò ãëþóóáò ãéá IDE.
ÄùñåÜí åñãáëåßá IDE -
Äåßôå ôï CDROM ôçò äéáíïìÞò redhat linux.
· Lesstiff Mottif Tool
<ftp://ftp.redhat.com/pub/contrib/i386/lesstiff*.rpm>
· FreeBuilder <ftp://ftp.redhat.com/pub/contrib/i386/free*.rpm>
· SpecTCL <ftp://ftp.redhat.com/pub/contrib/i386/spec*.rpm>
· JccWarrior <ftp://ftp.redhat.com/pub/contrib/i386/jcc*.rpm>
· Kanchenjunga Java RAD Tool for PostgreSQL
<http://www.man.ac.uk/~whaley/kj/kanch.html>
· Applixware Tool <http://www.redhat.com>
· XWPE X Windows Programming Environment
<http://www.rpi.edu/~payned/xwpe/>
<ftp://ftp.redhat.com/pub/contrib/i386/xwpe*.rpm>
· XWB X Windows Work Bench
<ftp://ftp.redhat.com/pub/contrib/i386/xwb*.rpm>
· NEdit <ftp://ftp.redhat.com/pub/contrib/i386/nedit*.rpm>
[1m10. Ïäçãïß Äéáóýíäåóçò ìå ôçí PostgreSQL[0m
[1m10.1. ODBC Drivers ãéá ôçí PostgreSQL[0m
ODBC åßíáé áêñùíýìéï ôïõ 'Open DataBase Connectivity', Ýíá äçìïöéëÝò
ðñüôõðï ãéá ðñüóâáóç óå ðëçñïöïñßåò áðü äéÜöïñåò âÜóåéò áðü
äéáöïñåôéêïýò ðùëçôÝò. Ïé åöáñìïãÝò ðïõ Ý÷ïõí ãñáöôåß ÷ñçóéìïðïéþíôáò
ODBC drivers, åããõïýíôáé üôé èá äïõëÝøïõí ìå äéÜöïñåò âÜóåéò üðùò
PostgreSQL, Oracle, Sybase, Informix êëð.
· Ôï PostODBC Ý÷åé óõìðåñéëçöèåß Þäç óôç äéáíïìÞ. Äåßôå ôï êåíôñéêü
web site <http://www.postgresql.org>. ÓõìðåñéëáìâÜíåôáé óôï CDROM
ôçò PostgreSQL.
· <http://www.openlinksw.com> Ç Open Link Software Corporation
ðïõëÜåé ODBC ãéá PostgreSQL êáé Üëëåò âÜóåéò. Ç Open Link äßíåé
åðßóçò äùñåÜí ODBC (ðåñéïñéóìÝíï áñéèìü ÷ñçóôþí) - ôóåêÜñåôÝ ôï.
· Insight ODBC ãéá ôçí PostgreSQL
<http://www.insightdist.com/psqlodbc> Áõôü åßíáé ôï åðßóçìï site
ôïõ PostODBC.
ÕðÜñ÷åé êÜðïéï Ýñãï ðïõ ïíïìÜæåôáé FreeODBC Pack Package. Äåí õðÜñ÷åé
ó' áõôü Ýêäïóç ãéá PostgreSQL, ßóùò ìðïñåßôå íá âïçèÞóåôå.
· <http://www.ids.net/~bjepson/freeODBC/> ÁõôÞ åßíáé ç äùñåÜí Ýêäïóç
ãéá ODBC.
[1m10.2. UDBC Drivers ãéá ôçí PostgreSQL[0m
Ôï UDBC åßíáé ìéá óôáôéêÞ Ýêäïóç ODBC áíåîÜñôçôç áðü äéá÷åéñéóôÝò
ïäçãþí (driver managers) êáé õðïóôÞñéîç DLL, ÷ñçóéìïðïéåßôáé ãéá íá
ðñïóèÝôåé õðïóôÞñéîç áðåõèåßáò äéáóýíäåóçò ìå âÜóç ìÝóá óôéò
åöáñìïãÝò.
· <http://www.openlinksw.com>Ç åôáéñåßá Open Link Software ðïõëÜ UDBC
ãéá ôçí PostgreSQL êáé Üëëåò âÜóåéò. Ç Open Link äßíåé åðßóçò
äùñåÜí UDBC (ðåñéïñéóìÝíï áñéèìü ÷ñçóôþí) - ôóåêÜñåôÝ ôï.
[1m10.3. JDBC Drivers ãéá ôçí PostgreSQL[0m
JDBC åßíáé áêñùíýìéï ôïõ 'Java DataBase Connectivity'. Ç Java åßíáé
ìéá ãëþóóá ðñïãñáììáôéóìïý áíåîáñôÞôïõ ðëáôöüñìáò ðïõ áíáðôý÷èçêå áðü
ôçí Sun Microsystems. Ïé ðñïãñáììáôéóôÝò Java åíèáññýíïíôáé íá
ãñÜöïõí åöáñìïãÝò âÜóåùí äåäïìÝíùí ÷ñçóéìïðïéþíôáò JDBC ãéá íá
äéåõêïëýíïõí ôç ìåôáöåñóéìüôçôá ìåôáîý âÜóåùí üðùò ç PostgreSQL,
Oracle, informix, êëð. Áí ãñÜøåôå åöáñìïãÞ óå Java ìðïñåßôå íá ðÜñåôå
ôïõò ïäçãïýò JDBC ãéá PostgreSQL áðü ôá ðáñáêÜôù sites:
Ï ïäçãüò JDBC ðåñéëáìâÜíåôáé Þäç óôç äéáíïìÞ ôçò PostgreSQL.
· <http://www.demon.co.uk/finder/postgres/index.html> Äéáóýíäåóç Java
(ôçò Sun) ìå PostgreSQL
· <ftp://ftp.ai.mit.edu/people/rst/rst-jdbc.tar.gz>
· <http://www.openlinksw.com> Ç åôáéñåßá Open Link Software ðïõëÜ
JDBC ãéá PostgreSQL êáé Üëëåò âÜóåéò. Ç Open Link äßíåé åðßóçò
äùñåÜí JDBC (ðåñéïñéóìÝíï áñéèìü ÷ñçóôþí) - ôóåêÜñåôÝ ôï.
· JDBC UK site <http://www.retep.org.uk/postgres>
· JDBC FAQ site <http://eagle.eku.edu/tools/jdbc/faq.html>
Ôá JDBC home, guide êáé FAQ âñßóêïíôáé óôá -
· JDBC HOME <http://splash.javasoft.com/jdbc>
· JDBC guide
<http://www.javasoft.com/products/jdk/1.1/docs/guide/jdbc>
· JDBC FAQ <http://javanese.yoyoweb.com/JDBC/FAQ.txt>
[1m10.4. Java ãéá PostgreSQL[0m
Ïé ðñïãñáììáôéóôÝò Java ìðïñåß íá èåùñÞóïõí ôá ðáñáêÜôù sites ðïëý
÷ñÞóéìá ãéá ôçí PostgreSQL.
· <ftp://ftp.redhat.com/pub/contrib/i386> êáé äåßôå ôï postgresql-
jdbc-*.rpm
· <http://www.blackdown.org>
[1m11. Perl Database Interface (DBI) Driver ãéá PostgreSQL[0m
[1m11.1. Äéáóýíäåóç Perl 5 ìå PostgreSQL[0m
PERL åßíáé áêñùíýìéï ôïõ 'Practical Extraction êáé Report Language'.
Ç Perl åßíáé äéáèÝóéìç ó÷åäüí óå êÜèå ëåéôïõñãéêü êáé ðëáôöüñìá
hardware. Ìðïñåßôå íá ÷ñçóéìïðïéÞóôå Perl óå Windows95/NT, üëá ôá Unix
(Solaris, HPUX, AIX, Linux, Irix, SCO êëð.), óå mainframe MVS, desktop
OS/2, OS/400, Amdahl UTS êáé ðïëëÜ Üëëá. Ç Perl ôñÝ÷åé [1mÁÊÏÌÇ [22mêáé óå
ðïëëÜ ìç äçìïöéëÞ/ãåíéêÜ Üãíùóôá ëåéôïõñãéêÜ óõóôÞìáôá êáé õëéêÜ!!
¸ôóé, ìçí åêðëáãåßôå áí äåßôå ôçí perl íá ôñÝ÷åé óå ðïëëÜ ü÷é óõ÷íÜ
÷ñçóéìïðïéïýìåíá ëåéôïõñãéêÜ.
Ìðïñåßôå íá öáíôáóôåßôå ôçí ôåñÜóôéá âÜóç ÷ñçóôþí êáé ðñïãñáììáôéóôþí
óå Perl.
Ç äéáóýíäåóç Perl ìå PostgreSQL ðåñéëáìâÜíåôáé óôç äéáíïìÞ ôçò
PostgreSQL. ÊïéôÜîôå óôïí êáôÜëïãï src/pgsql_perl5.
· Ôï Email ãéá åðéêïéíùíßá ó÷åôéêÜ ìå ôçí Pgsql_perl5 :
E.Mergl@bawue.de
· ¶ëëç ðçãÞ åßíáé ôá -
<ftp://ftp.kciLink.com/pub/PostgresPerl-1.3.tar.gz>
· Perl Home page: <http://www.perl.com/perl/index.html>
· ÅêìÜèçóç ôçò Perl, øÜîôå ãéá ôßôëï Tutorial óôï :
<http://reference.perl.com/>
· Ôï Perl FAQ åßíáé óôï :
<http://www.yahoo.com/Computers_and_Internet/Programming_Languages/Perl/>
· Ãñáöéêü ðåñéâÜëëïí ãéá Perl, Perl-Qt :
<ftp://ftp.redhat.com/pub/contrib/i386> êáé øÜîôå ãéá ôï
PerlQt-1.06-1.i386.rpm
· Ãñáöéêü ðåñéâÜëëïí ãéá Perl, Perl-Qt :
<http://www.accessone.com/~jql/perlqt.html>
· Ãñáöéêü ðåñéâÜëëïí ãéá Perl, Perl-XForms :
<ftp://ftp.redhat.com/pub/contrib/i386> êáé øÜîôå ãéá ôï áñ÷åßï
Xforms4Perl-0.8.4-1.i386.rpm
· Ãñáöéêü ðåñéâÜëëïí ãéá Perl, Perl-Tk :
<ftp://ftp.redhat.com/pub/contrib/i386>
· Perl GUIkits : <http://reference.perl.com/query.cgi?ui>
· Perl Database Interfaces :
<http://reference.perl.com/query.cgi?database>
· ÌåôáöñáóôÞò áðü Perl óå "C" : <http://www.perl.com/CPAN-
local/modules/by-module/B/> êáé øÜîôå ãéá ôï Compiler-a3.tar.gz
· ÌåôáöñáóôÞò áðü Perl óå êÝëõöïò Bourne :
<http://www.perl.com/CPAN/authors/id/MERLYN/sh2perl-0.02.tar.gz>
· áðü awk óå perl a2p êáé áðü sed óå perl s2p ðåñéëáìâÜíåôáé ìå ôç
äéáíïìÞ ôçò PERl.
· Äåßôå åðßóçò ôá newsgroups ãéá PERL óôï comp.lang.perl.*
[1m11.2. Perl Database Interface DBI[0m
[1m11.2.1. ÔÉ ÅÉÍÁÉ ÔÏ DBI ;[0m
Ôï ðáñáêÜôù åßíáé [1máðüóðáóìá [22máðü ôçí êåíôñéêÞ óåëßäá ôïõ Perl DBI.
To Perl Database Interface (DBI) åßíáé Ýíá ðñïãñáììáôéóôéêü interface
(API) óå Perl ãéá äéáóýíäåóç ìå âÜóåéò äåäïìÝíùí. Ïé ðñïóäéïñéóìïß
ôïõ Perl DBI API ïñßæïõí Ýíá óýíïëï áðü ñïõôßíåò, ìåôáâëçôÝò êáé
óõìâÜóåéò ðïõ ðáñÝ÷ïõí Ýíá óõíåêôéêü interface âÜóçò äåäïìÝíùí
áíåîÜñôçôï áðü ôçí ðñáãìáôéêÞ âÜóç ðïõ ÷ñçóéìïðïéåßôáé. Ïé
ðëçñïöïñßåò ãéá áõôü ôï ôìÞìá DBI ðñïÞëèå áðü ôï êåßìåíï 'DBI FAQ' ôï
ïðïßï Ý÷åé ãñÜøåé ï Alligator Descartes ôï áíáðáñáãÜãáìå ìå ôçí ÜäåéÜ
ôïõ.
· Ìðïñåßôå íá åðéêïéíùíÞóåôå ìå ôïí Alligator Descartes Hermetica óôï
descarte@hermetica.com
[1m11.2.2. Ïäçãüò DBI ãéá ôçí PostgreSQL - DBD-Pg-0.89[0m
ÊáôåâÜóôå ôï DBD-Pg-0.89.tar.gz áðü ôá
· DBD-Pg-0.89 : <http://www.perl.com/CPAN/modules/by-module/DBD/>
· Comprehensive Perl Archive Network CPAN <http://www.perl.com/CPAN>
· Ëßóôá ïäçãþí DBI êáé óåëßäåò DBI module
<http://www.hermetica.com/technologia/perl/DBI>
· Ðëçñïöïñßåò ãéá ôï DBI èá âñåßôå óôï <http://www.fugue.com/dbi/>
· Êåíôñéêü ftp site <ftp://ftp.demon.co.uk/pub/perl/db>
· ÄéÜöïñá DBI link <http://www-ccs.cs.umass.edu/db.html>
· ÄéÜöïñá DBI link <http://www.odmg.org/odmg93/updates_dbarry.html>
· ÄéÜöïñá DBI link <http://www.jcc.com/sql_stnd.html>
· Ç âÜóç PostgreSQL <http://www.postgresql.org>
ÁÐÁÉÔÇÓÅÉÓ:
· - íá ÷ôßóåôå, íá ôåóôÜñåôå êáé íá åãêáôáóôÞóåôå ôçí Perl 5
(ôïõëÜ÷éóôïí ôçí 5.002)
· - íá ÷ôßóåôå, íá ôåóôÜñåôå êáé íá åãêáôáóôÞóåôå ôï module DBI
(ôïõëÜ÷éóôïí ôï 0.89)
· - íá ÷ôßóåôå, íá ôåóôÜñåôå êáé íá åãêáôáóôÞóåôå ôçí PostgreSQL
(ôïõëÜ÷éóôïí ôçí 6.2)
[1m11.2.3. Ôå÷íéêÞ õðïóôÞñéîç ãéá ôï DBI[0m
Ðáñáêáëþ óôåßëôå ôá ó÷üëéÜ óáò êáé áíáöïñÝò ëáèþí óôï
· E.Mergl@bawue.de
ÓõìðåñéëÜâåôå ðáñáêáëþ ôçí Ýîïäï ôçò åíôïëÞ perl -v, êáé perl -V, ôçí
Ýêäïóç ôçò PostgreSQL, ôçí Ýêäïóç ôïõ DBD-Pg, êáé ôçí Ýêäïóç ôïõ DBI
óôçí áíáöïñÜ ëáèþí.
[1m11.2.4. Ôé åßíáé ôá DBI, DBperl, Oraperl êáé *perl;[0m
¼ðùò åßðå êáé ï Tim Bunce, ï ó÷åäéáóôÞò êáé óõããñáöÝáò ôïõ DBI:
``Ôï DBI åßíáé Ýíá ðñïãñáììáôéóôéêü interface (API) óå Perl ãéá
äéáóýíäåóç ìå äéáóýíäåóç ìå âÜóåéò äåäïìÝíùí. Ïé ðñïóäéïñéóìïß ôïõ DBI
API ïñßæïõí Ýíá óýíïëï áðü ñïõôßíåò, ìåôáâëçôÝò êáé óõìâÜóåéò ðïõ
ðáñÝ÷ïõí Ýíá óõíåêôéêü interface âÜóçò äåäïìÝíùí áíåîÜñôçôï áðü ôçí
ðñáãìáôéêÞ âÜóç ðïõ ÷ñçóéìïðïéåßôáé.''
Ìå áðëÜ ëüãéá, ôï DBI interface åðéôñÝðåé óôïõò ÷ñÞóôåò íá Ý÷ïõí
äéÜöáíç ðñüóâáóç óå ðïëëáðëïýò ôýðïõò âÜóåùí. ¸ôóé, áí óõíäÝåóôå ôçí
Oracle, Informix, mSQL, Sybase Þ ïðïéáäÞðïôå Üëëç âÜóç, äå ÷ñåéÜæåôáé
íá ãíùñßæåôå ôïõò õðïêåßìåíïõò ìç÷áíéóìïýò ôïõ åðéðÝäïõ 3GL. Ôï API
ðïõ ïñßæåôáé áðü ôï DBI èá äïõëÝøåé óå üëïõò ôïõò ôýðïõò âÜóåùí.
¸íá ðáñüìïéï ðëåïíÝêôçìá åßíáé ç éêáíüôçôá íá óõíäåèåßôå óå äýï âÜóåéò
äéáöïñåôéêïý ôýðïõ ìÝóù ôïõ ßäéïõ perl script, ð÷, èÝëåôå íá
äéáâÜóåôå äåäïìÝíá áðü ìéá âÜóç Oracle êáé íá ôá åéóÜãåôå óå ìéá âÜóç
Informix ìÝóá óôï ßäéï ðñüãñáììá. Ôï åðßðåäï DBI óáò åðéôñÝðåé íá ôï
êÜíåôå áõôü áðëÜ êáé éó÷õñÜ.
DBperl åßíáé ôï ðáëéü üíïìá ãéá ôéò ðñïäéáãñáöÝò ôïõ interface.
×ñçóéìïðïéåßôáé óõíÞèùò ãéá íá õðïäçëþóåé ôá perl4 modules ãéá
äéáóýíäåóç ìå âÜóåéò, üðùò, oraperl, isqlperl, ingperl êáé ëïéðÜ. ÁõôÜ
ôá interfaces äåí åß÷áí óôÜíôáñ API êáé ãåíéêÜ äåí õðïóôçñßæïíôáé.
Íá ìéá ëßóôá áðü DBperl modules, ôï áíôßóôïé÷ï DBI ôáßñé ôïõò êáé
ðëçñïöïñßåò õðïóôÞñéîçò. ÅñùôÞóåéò ó÷åôéêÜ ìå ôïí ïäçãü DBI èá ðñÝðåé
íá áðåõèýíïíôáé óôç ëßóôá áëëçëïãñáößáò dbi-users .
¼íïìá Module Áðáéôïýìåíç ÂÜóç ÓõããñáöÝáò DBI
------------ ----------------- ---------- ---
Sybperl Sybase Michael Peppler DBD::Sybase
<mpeppler@datamig.com>
http://www.mbay.net/~mpeppler
Oraperl Oracle 6 & 7 Kevin Stock DBD::Oracle
<dbi-users@fugue.com>
Ingperl Ingres Tim Bunce & DBD::Ingres
Ted Lemon
<dbi-users@fugue.com>
Interperl Interbase Buzz Moschetti DBD::Interbase
<buzz@bear.com>
Uniperl Unify 5.0 Rick Wargo -
<rickers@coe.drexel.edu>
Pgperl Postgres Igor Metz DBD::Pg
<metz@iam.unibe.ch>
Btreeperl NDBM John Conover SDBM;
<john@johncon.com>
Ctreeperl C-Tree John Conover -
<john@johncon.com>
Cisamperl Informix C-ISAM Mathias Koerber -
<mathias@unicorn.swi.com.sg>
Duaperl X.500 Directory Eric Douglas -
User Agent
Ðáñüëá áõôÜ, ìåñéêÜ DBI modules Ý÷ïõí åðßðåäá ðñïóïìïßùóçò DBperl.
¸ôóé, ç DBD::Oracle Ýñ÷åôáé ìå Ýíá åðßðåäï ðñïóïìïßùóçò Oraperl, ðïõ
óáò åðéôñÝðåé íá ôñÝîåôå êëçñïíïìéêÜ oraperl scripts ÷ùñßò áëëáãÝò. Ôï
åðßðåäï ðñïóïìïßùóçò ìåôáöñÜæåé ôéò êëÞóåéò ôïõ oraperl API óå êëÞóåéò
DBI êáé ôéò åêôåëåß ìÝóù ôïõ DBI switch.
Íá Ýíáò ðßíáêáò ìå ðëçñïöïñßåò ãéá ôá åðßðåäá ðñïóïìïßùóçò :
Module Åðßðåäï ðñïóïìïßùóçò ÊáôÜóôáóç
------ --------------------- ------
DBD::Oracle Oraperl ÏëïêëçñùìÝíï
DBD::Informix Isqlperl Õðü áíÜðôõîç
DBD::Sybase Sybperl Äïõëåýåé; (÷ñåéÜæåôáé åðáëÞèåõóç )
DBD::mSQL Msqlperl Åêäüèçêå ðåéñáìáôéêÜ ìå ôçí
DBD::mSQL-0.61
Ç ðñïóïìïßùóç Msqlperl åßíáé ìéá åéäéêÞ ðåñßðôùóç. Ôï Msqlperl åßíáé
Ýíáò ïäçãüò perl5 ãéá mSQL âÜóåéò, áëëÜ äå óõììïñöþíåôáé ìå ôéò
ðñïäéáãñáöÝò ôïõ DBI. Ç ÷ñÞóç áðïäïêéìÜæåôáé ñçôÜ ãéá ÷Üñç ôïõ
DBD::mSQL. Ìðïñåßôå íá êáôåâÜóåôå ôçí Msqlperl áðü ôç CPAN áðü ôï:
· <http://www.perl.com/cgi-bin/cpan_mod?module=Msqlperl>
[1m11.2.5. ÐñïäéáãñáöÝò DBI[0m
ÕðÜñ÷ïõí ëßãåò ðçãÝò ðëçñïöïñßáò ãéá DBI.
· ÐñïäéáãñáöÝò DBI
<http://www.hermetica.com/technologia/perl/DBI/doc/dbispec>
ÕðÜñ÷ïõí äýï ðñïäéáãñáöÝò äéáèÝóéìåò óå áõôü ôï link, ïé íÝåò
Ðñü÷åéñåò (Draft) DBI ðñïäéáãñáöÝò, áõôü ôï êåßìåíï áëëÜæåé êáèçìåñéíÜ
êáèþò ç ïìÜäá áíÜðôõîçò âáäßæåé ïñïò Ýíá óôáèåñü interface, êáé ïé
ðáëéÝò éóôïñéêÝò DBperl ðñïäéáãñáöÝò áðü ôéò ïðïßåò áíáðôý÷èçêå ôï
ôñÝ÷ïí DBI interface.
Ôï ôåëåõôáßï êåßìåíï ðñÝðåé íá äéáâáóôåß ìüíï êáé ìüíï áðü éóôïñéêü
åíäéáöÝñïí êáé íá ìç ÷ñçóéìïðïéçèåß ùò åã÷åéñßäéï ðñïãñáììáôéóìïý, Þ
ùò Ýãêõñï ìå ïðïéáäÞðïôå Ýííïéá. Ðáñüëá áõôÜ, ðáñáìÝíåé ìéá áêüìç
÷ñÞóéìç ðçãÞ áíáöïñÜò.
Ôåêìçñßùóç POD Ôá PODs åßíáé êïììÜôéá ôåêìçñßùóçò ðïõ åíóùìáôþíïíôáé
óõíÞèùò óå ðñïãñÜììáôá perl ðïõ ôåêìçñéþíïõí ôïí êþäéêá ``in place'',
ðáñÝ÷ïíôáò Ýíá ÷ñÞóéìï âïÞèçìá ãéá ðñïãñáììáôéóôÝò êáé ÷ñÞóôåò
modules. Ôï POD ãéá DBI êáé drivers ãßíåôáé üëï êáé ðåñéóóüôåñï
êïéíüôïðï, êáé ç ôåêìçñßùóç ãéá áõôÜ ôá modules ìðïñåß íá äéáâáóôåß ìå
ôéò ðáñáêÜôù åíôïëÝò.
ÐñïäéáãñáöÝò DBI Ôá POD ãéá ðñïäéáãñáöÝò DBI ìðïñåß íá äéáâáóôåß ìå
ôçí åíôïëÞ:
perldoc DBI
Oraperl Ïé ÷ñÞóôåò ôïõ åðéðÝäïõ ðñïóïìïßùóçò Oraperl ðïõ Ýñ÷åôáé ìáæß
ìå ôçí DBD::Oracle, ìðïñïýí íá óõíå÷ßóïõí íá äéáâÜóïõí ãéá ôï ðùò íá
ðñïãñáììáôßóïõí ìå ôï Oraperl ðëçêôñïëïãþíôáò:
perldoc Oraperl
Áõôü èá ðáñÜãåé Ýíá åíçìåñùìÝíï áíôßãñáöï ôçò áñ÷éêÞò óåëßäáò âïçèåßáò
oraperl, ðïõ ãñÜöôçêå áðü ôïí Kevin Stock ãéá perl4. Ôï API ôçò
oraperl åìöáíßæåôáé êáé ðåñéãñÜöåôáé åêåß ðëÞñùò.
DBD::mSQL Ïé ÷ñÞóôåò ôïõ DBD::mSQL module ìðïñïýí íá äéáâÜóïõí ãéá
ìåñéêÝò private functions êáé éäéïìïñößåò áõôïý ôïõ ïäçãïý (driver)
ðëçêôñïëïãþíôáò:
perldoc DBD::mSQL
Óõ÷íÜ ÄéáôõðùìÝíåò ÅñùôÞóåéò (FAQ)
To êåßìåíï, Frequently Asked Questions åßíáé åðßóçò äéáèÝóéìï ùò
ôåêìçñßùóç óå POD ! Ìðïñåßôå íá ôï äéáâÜóåôå óôï äéêü óáò óýóôçìá,
ðëçêôñïëïãþíôáò:
perldoc DBI::FAQ
Áõôü ìðïñåß íá åßíáé âïëéêüôåñï ãéá áíèñþðïõò ðïõ äåí åßíáé
óõíäåäåìÝíïé ìüíéìá Þ Üíåôá, óôï Internet.
Ôï POD ãåíéêÜ Ðëçñïöüñçóç ãéá ôç óõããñáöÞ POD, êáé ãéá ôçí öéëïóïößá
ôïõ POD ãåíéêüôåñá, ìðïñåß íá äéáâáóôåß ãñÜöïíôáò:
perldoc perlpod
×ñÞóôåò ðïõ Ý÷ïõí åãêáôáóôÞóåé ôï Tk module ßóùò íá åíäéáöÝñïíôáé íá
ìÜèïõí ðùò õðÜñ÷åé äéáèÝóéìïò Ýíáò POD áíáãíþóôçò âáóéóìÝíïò óå Tk ðïõ
ëÝãåôáé tkpod, êáé äéáìïñöþíåé POD óå ìéá âïëéêÞ êáé áíáãíþóéìç ìïñöÞ.
``ÐåñéðëáíÞóåéò'', ``ÌåæåäÜêéá'' êáé ÐáñáôçñÞóåéò ÕðÜñ÷åé ìéá óåéñÜ
áðü ðåñéóôáóéáêÝò ``ðåñéðëáíÞóåéò'' áðü äéÜöïñïõò óôéò ëßóôåò
áëëçëïãñáößáò ãéá DBI.
· <http://www.hermetica.com/technologia/perl/DBI/tidbits>
``DBI -- The perl5 Database Interface'' Áõôü åßíáé Ýíá Üñèñï áðü ôïí
Alligator Descartes êáé ôïí Tim Bunce ãéá ôç äïìÞ ôïõ DBI.
Äçìïóéåýôçêå óôï ôåý÷ïò 5 ôïõ ``The Perl Journal''. Åßíáé õðåñâïëéêÜ
êáëü. Ðçãáßíåôå êáé áãïñÜóôå ôï ðåñéïäéêü. Åäþ ðïõ ôá ëÝìå, áãïñÜóôå
üëá ôá ôåý÷ç! ``The Perl Journal''s WWW site is:
· <http://www.tpj.com>
``DBperl'' Áõôü ôï Üñèñï, ôï ïðïßï äçìïóéåýôçêå óôçí Ýêäïóç Íïåìâñßïõ
ôïõ 1996 ``Dr. Dobbs Journal'' áó÷ïëåßôáé ìå DBperl.
``The Perl5 Database Interface'' Áõôü åßíáé Ýíá âéâëßï ãñáììÝíï áðü
ôïí Alligator Descartes êáé åêäüèçêå áðü ôïõò O'Reilly êáé Associates.
Ëßóôåò Áëëçëïãñáößáò õðÜñ÷ïõí ôñåéò ëßóôåò áëëçëïãñáößáò ãéá DBI ðïõ
äéá÷åéñßæåôáé ï Ted Lemon. Óå üëåò ìðïñåßôå íá ãñáöôåßôå êáé íá
îåãñáöôåßôå áðü ôï World Wide Web óôç äéåýèõíóç :
· Ëßóôåò áëëçëïãñáößáò <http://www.fugue.com/dbi>
Ïé ëßóôåò óôéò ïðïßåò ìðïñïýí íá óõììåôÝ÷ïõí ïé ÷ñÞóôåò åßíáé:
[1mdbi-announce [22mÁõôÞ ç ëßóôá áëëçëïãñáößáò ìüíï ãéá áíáêïéíþóåéò. Áí äåí
ìðïñåßôå íá ÷ñçóéìïðïéÞóåôå ôçí öüñìá ôçò ðáñáðÜíù WWW óåëßäáò,
åããñáöåßôå óôç ëßóôá ìå ôïí áêüëïõèï ôñüðï:
· Email: dbi-announce-request@fugue.com
ìå êåßìåíï óôï óþìá (body) ôïõ ìçíýìáôïò 'subscribe'
[1mdbi-dev [22mÇ ëßóôá áõôÞ óôï÷åýåé óå ÷ñÞóç áðü ôïõò ðñïãñáììáôéóôÝò ðïõ
êÜíïõí áíÜðôõîç, ðïõ óõæçôÜíå éäÝåò êáé Ýííïéåò ãéá ôá ôùí DBI
interface, API êáé driver. Áí äåí ìðïñåßôå íá ÷ñçóéìïðïéÞóåôå ôçí
öüñìá ôçò ðáñáðÜíù WWW óåëßäáò, åããñáöåßôå óôç ëßóôá ìå ôïí áêüëïõèï
ôñüðï:
· Email: dbi-dev-request@fugue.com
ìå êåßìåíï óôï óþìá (body) ôïõ ìçíýìáôïò 'subscribe'
[1mdbi-users [22mÁõôÞ ç ëßóôá áëëçëïãñáößáò åßíáé ìéá ëßóôá ãåíéêþí
óõæçôÞóåùí ðïõ ÷ñçóéìïðïéåßôáé ãéá áíáöïñÝò óöáëìÜôùí, óõæÞôçóç
ðñïâëçìÜôùí êáé ãåíéêÝò áíáæçôÞóåéò. Áí äåí ìðïñåßôå íá
÷ñçóéìïðïéÞóåôå ôçí öüñìá ôçò ðáñáðÜíù WWW óåëßäáò, åããñáöåßôå óôç
ëßóôá ìå ôïí áêüëïõèï ôñüðï:
· Email: dbi-users-request@fugue.com
ìå êåßìåíï óôï óþìá (body) ôïõ ìçíýìáôïò 'subscribe'
×ñïíéêÜ/Áñ÷åßá ôùí Ëéóôþí Áëëçëïãñáößáò
· ÁìåñéêÜíéêá Áñ÷åßá Ëéóôþí Áëëçëïãñáößáò
<http://outside.organic.com/mail-archives/dbi-users/>
· ÅõñùðáúêÜ Áñ÷åßá Ëéóôþí Áëëçëïãñáößáò <http://www.rosat.mpe-
garching.mpg.de/mailing-lists/PerlDB-Interest>
[1m11.2.6. ÐñïâëÞìáôá Ìåôáãëþôôéóçò Þ áëëéþò "Êüðçêå óôéò ÅîåôÜóåéò!"[0m
Áí Ý÷åôå core dump, äïêéìÜóôå ôï module Devel::CoreStack ãéá íá
äçìéïõñãÞóåôå Ýíá stack trace áðü ôï core dump. Ôï Devel::CoreStack
âñßóêåôáé óôï CPAN óôï:
· <http://www.perl.com/cgi-bin/cpan_mod?module=Devel::CoreStack>
Óôåßëôå Email óôç ëßóôá dbi-users ôï stack trace, ôçí Ýêäïóç ôùí
modules, ôçò perl, ôá ôåóô ðïõ êÜíáôå, ôçí Ýêäïóç ôïõ ëåéôïõñãéêïý
óõóôÞìáôïò êáé üðïéåò Üëëåò ó÷åôéêÝò ðëçñïöïñßåò. ¼óåò ðåñéóóüôåñåò
ðëçñïöïñßåò óôåßëåôå, ôüóï ãñçãïñüôåñá èá áíé÷íåýóïõí ïé
ðñïãñáììáôéóôÝò ôá ðñïâëÞìáôá. Áí äå ìáò óôåßëôå ôßðïôá, ôüôå ìçí
ðåñéìÝíåôå ôßðïôá êáé áðü åìÜò.
-->
[1m11.2.7. Õðïóôçñßæåôáé ôï DBI êÜôù áðü ðëáôöüñìåò Windows 95 / NT ;[0m
Ç ìåôáöïñÜ ôùí DBI êáé DBD::Oracle Win32 åßíáé ôþñá Ýíá óôÜíôáñ ôìÞìá
ôïõ DBI, Ýôóé, áí êáôåâÜóåôå Ýêäïóç ôïõ DBI ìåãáëýôåñç ôïõ 0.81 èá
ðñÝðåé íá äïõëåýåé ìéá ÷áñÜ. Ìðïñåßôå íá Ý÷åôå ðñüóâáóç óôéò âÜóåéò
Microsoft Access êáé SQL-Server áðü ôï DBI ìÝóù ODBC. Ìáæß ìå ôï
DBI-0.79 (êáé ìåôÝðåéôá) äßíåôáé Ýíá ðåéñáìáôéêü DBI 'åðßðåäï
ðñïóïìïßùóçò' ãéá ôï module Win32::ODBC. ÏíïìÜæåôáé DBI::W32ODBC. Èá
÷ñåéáóôåßôå ôï module Win32::ODBC.
· Win32 DBI <http://www.hermetica.com/technologia/perl/DBI/win32>
· Win32 ODBC <http://www.roth.net>
[1m11.2.8. ôïõ; Ôé åßíáé ôï DBM; Êáé ãéáôß èá ðñÝðåé íá ÷ñçóéìïðïéþ ôï[0m
[1mDBI óôç èÝóç[0m
Ôï UNIX åõëïãÞèçêå áðü ôçí áñ÷Þ ìå áðëÝò ``âÜóåéò'' âáóéóìÝíåò óå
åðßðåäá áñ÷åßá, ãíùóôÝò óáí óýóôçìá dbm. Ôï dbm óáò åðéôñÝðåé íá
áðïèçêåýåôå äåäïìÝíá óå áñ÷åßá, êáé íá áíáêôÜôå ôá äåäïìÝíá ãñÞãïñá
ÐáñüëáõôÜ, áõôü Ý÷åé êáé óïâáñÜ ìåéïíåêôÞìáôá.
Êëåßäùìá Áñ÷åßùí (File Locking)
Ôá óõóôÞìáôá dbm äåí ðáñåß÷áí éäéáßôåñá éó÷õñÝò äõíáôüôçôåò ãéá
êëåßäùìá áñ÷åßùí, ïýôå êáìßá éêáíüôçôá ãéá ôç äéüñèùóç ðñïâëçìÜôùí ðïõ
ðñïÝêõðôáí áðü ôáõôü÷ñïíåò åããñáöÝò [óôç âÜóç].
Áõèáßñåôåò ÄïìÝò ÄåäïìÝíùí (Arbitrary Data Structures)
Ôá óõóôÞìáôá dbm åðéôñÝðïõí ìüíï ìéá óôáèåñÞ äïìÞ äåäïìÝíùí: æåõãÜñéá
êëåéäéþí-ôéìþí (key-value pairs). ÁõôÞ ç ôéìÞ ìðïñåß íá åßíáé Ýíá
óýíèåôï áíôéêåßìåíï, üðùò Ýíá [ C ] struct, áëëÜ ôï êëåéäß ðñÝðåé íá
åßíáé ìïíáäéêü. Áõôü Þôáí ìåãÜëïò ðåñéïñéóìüò óôç ÷ñçóéìüôçôá ôùí
óõóôçìÜôùí dbm.
ÐáñüëáõôÜ, ôá óõóôÞìáôá dbm áêüìá åßíáé ÷ñÞóéìá ãéá ÷ñÞóôåò ìå áðëÜ
óýíïëá äåäïìÝíùí êáé ðåñéïñéóìÝíïõò ðüñïõò, ìéá êáé åßíáé ãñÞãïñá,
äõíáôÜ êáé åîáéñåôéêÜ êáëÜ åëåãìÝíá. Ôá modules ôçò Perl ãéá ôçí
ðñüóâáóç óå óõóôÞìáôá dbm Ý÷ïõí åíóùìáôùèåß ôþñá óôçí äéáíïìÞ ôçò,
ìÝóù ôïõ module AnyDBM_File.
ÐåñéëçðôéêÜ, ôï DBM åßíáé ìéá éêáíïðïéçôéêüôáôç ëýóç ãéá (êáôÜ êáíüíá)
read-only âÜóåéò, Þ ìéêñÜ êáé áðëÜ óýíïëá äåäïìÝíùí. ÐáñüëáõôÜ, ãéá
ðåñéóóüôåñï éó÷õñÜ êáé åðåêôÜóéìá óýíïëá äåäïìÝíùí, ÷ùñßò ïýôå êáí íá
áíáöåñèïýìå êáé óå áîéüðéóôï transactional locking, óõíéóôïýìå óôïõò
÷ñÞóôåò íá ÷ñçóéìïðïéÞóïõí DBI.
[1m11.2.9. Õðïóôçñßæåôáé < ôï ôÜäå ÷áñáêôçñéóôéêü > óôï DBI;[0m
Èåùñþíôáò üôé ôï ÷áñáêôçñéóôéêü ðïõ æçôÞóáôå åßíáé Ýíá ìç-óôÜíôáñ,
åîáñôþìåíï áðü êÜðïéá óõãêåêñéìÝíç âÜóç, ÷áñáêôçñéóôéêü, ôüôå ç
áðÜíôçóç åßíáé ü÷é.
Ôï DBI áíôáíáêëÜ Ýíá ãåíéêü API ðïõ èá äïõëÝøåé ãéá ôéò ðåñéóóüôåñåò
âÜóåéò, êáé äåí ðáñÝ÷åé êáìßá åðéðëÝïí ëåéôïõñãéêüôçôá ãéá êÜðïéá
óõãêåêñéìÝíç âÜóç äåäïìÝíùí (database-specific functionality).
ÐáñüëáõôÜ, ïé óõããñáöåßò ôùí ïäçãþí ìðïñïýí, áí ôï åðéèõìïýí, íá
óõìðåñéëÜâïõí hooks ðñïò åîåéäéêåõìÝíåò ëåéôïõñãßåò/÷áñáêôçñéóôéêÜ
êÜðïéáò âÜóçò äåäïìÝíùí ìÝóù ôçò ìåèüäïõ func ðïõ ïñßæåôáé óôï DBI
API. ¼óïé áíáðôýóóïõí scripts èá ðñÝðåé íá óçìåéþóïõí ðùò ç
ëåéôïõñãéêüôçôá ðïõ ðáñÝ÷åôáé ìÝóù ôùí ìåèüäùí func åßíáé áðßèáíï íá
ìåôáöåñèåß óå Üëëåò âÜóåéò.
[1m11.2.10. ×ñçóéìåýåé êáèüëïõ ôï DBI ãéá ðñïãñáììáôéóìü óå CGI;[0m
Ìå ìéá ëÝîç, íáé! Ôï DBI åßíáé åîáéñåôéêÜ ÷ñÞóéìï ãéá ðñïãñáììáôéóìü
óå CGI! Óôçí ðñáãìáôéêüôçôá, èá ôïëìïýóá íá ðù üôé ï ðñïãñáììáôéóìüò
óå CGI åßíáé ìßá áðü ôéò êýñéåò ÷ñÞóåéò ôïõ DBI.
To DBI äßíåé ôçí éêáíüôçôá óôïõò ðñïãñáììáôéóôÝò CGI íá åíéó÷ýóïõí ôéò
âÜóåéò ðïõ Ý÷ïõí WWW-fronted, ðñÜãìá ðïõ ðáñÝ÷åé óôïõò ÷ñÞóôåò ôç
äõíáôüôçôá íá ðáßîïõí ìå ôåñÜóôéåò ðïóüôçôåò äïìçìÝíùí äåäïìÝíùí.
Åðßóçò, óôçí ðåñßðôùóç ðïõ Ýíá site Ý÷åé ðåñéóóüôåñç êßíçóç áðü üôé ï
server ôçò âÜóçò äåäïìÝíùí ìðïñåß íá áíôéìåôùðßóåé, ôï DBI äßíåé ôç
äõíáôüôçôá áíáâÜèìéóçò ôïõ server ôçò âÜóçò äåäïìÝíùí óôï ðáñáóêÞíéï,
÷ùñßò áëëáãÝò óôá cgi scripts.
[1m11.2.11. Ðþò ðåôõ÷áßíù ôá÷ýôåñïõò ÷ñüíïõò óýíäåóçò ìå DBD Oracle êáé[0m
[1mCGI;[0m
Ï Apache httpd äéáôçñåß ìéá äåîáìåíÞ (pool) áðü ðáéäéÜ ôïõ (httpd
children) ãéá íá åîõðçñåôïýí ôéò áéôÞóåéò ôùí clients.
×ñçóéìïðïéþíôáò ôï module ôïõ Apache mod_perl ôïõ Doug MacEachern, ï
ìåôáöñáóôÞò ôçò perl (perl interpreter) åíóùìáôþíåôáé óôá ðáéäéÜ ôïõ
httpd. Ôá CGI, DBI, êáé ôá õðüëïéðá áãáðçìÝíá óáò modules ìðïñïýí íá
öïñôùèïýí êáôÜ ôçí åêêßíçóç êÜèå ðáéäéïý (child). ÁõôÜ ôá modules äå
èá îáíáöïñôùèïýí åÜí äåí áëëÜîïõí óôï äßóêï.
Ãéá ðåñéóóüôåñåò ðëçñïöïñßåò ó÷åôéêÜ ìå ôïí Apache, äåßôå ôï Apache
Project's WWW site:
· Apache Project WWW site <http://www.apache.org>
· Mod_perl module <http://www.perl.com/cgi-
bin/cpan_mod?module=mod_perl>
[1m11.2.12. Ðþò åðéôõã÷Üíù ìüíéìåò (persistent) óõíäÝóåéò ìåôáîý DBI êáé[0m
[1mCGI[0m
×ñçóéìïðïéþíôáò ôï module Apache::DBI module ôïõ Edmund Mergl, ôá
logins óôç âÜóç äåäïìÝíùí áðïèçêåýïíôáé êáé áíôéóôïé÷ßæïíôáé óå Ýíá
httpd child. Áí ç åöáñìïãÞ óáò âáóßæåôáé óå Ýíáí ìüíï ÷ñÞóôç ôçò
âÜóçò äåäïìÝíùí, ç óýíäåóç ìðïñåß íá ãßíåôáé ìå êÜèå child. ÌÝ÷ñé
óÞìåñá, ïé óõíäÝóåéò óôéò âÜóåéò äåäïìÝíùí äåí ìðïñïýí íá ìïéñÜæïíôáé
ìåôáîý äéáöïñåôéêþí ðáéäéþí ôïõ httpd.
Ìðïñåßôå íá êáôåâÜóåôå ôï Apache::DBI áðü ôç CPAN ìÝóù:
· <http://www.perl.com/cgi-bin/cpan_mod?module=Apache::DBI>
[1m11.2.13. ôï ôñÝ÷ù áðü ôïí httpd, áðïôõã÷Üíåé!'' Ãéáôß; ``¼ôáí ôñÝ÷ù[0m
[1mÝíá perl script áðü ôçí ãñáììÞ åíôïëÞò, äïõëåýåé, áëëÜ üôáí[0m
ÂáóéêÜ, Ýíáò ëüãïò ãéá ôïí ïðïßï ìðïñåß íá óõìâáßíåé áõôü åßíáé üôé ï
÷ñÞóôçò áðü ôïí ïðïßï ôñÝîáôå ôï script óôç ãñáììÞ åíôïëþí Ý÷åé óùóôÜ
ñõèìéóìÝíá ôéò ìåôáâëçôÝò ôïõ ðåñéâÜëëïíôïò, óôçí ðåñßðôùóç ôïõ
DBD::Oracle, ìåôáâëçôÝò üðùò $ORACLE_HOME, $ORACLE_SID Þ TWO_TASK.
Ç äéåñãáóßá httpd ôñÝ÷åé óõíÞèùò êÜôù áðü ôï ÷ñÞóôç nobody, ðñÜãìá ðïõ
óçìáßíåé üôé äåí Ý÷åé ñõèìéóìÝíï ôï ðåñéâÜëëïí ôïõ. ÏðïéïäÞðïôå script
åðé÷åéñÞóåé íá ôñÝîåé êÜôù áðü áõôÞí ôçí êáôÜóôáóç èá áðïôý÷åé
óßãïõñá.
Ãéá íá ëýóåôå áõôü ôï ðñüâëçìá, èÝóôå ôï ðåñéâÜëëïí ãéá ôç âÜóç óáò óå
Ýíá ìðëïê BEGIN ( ) óôçí áñ÷Þ ôïõ script óáò. ¸ôóé èá äéïñèùèåß ôï
ðñüâëçìá.
Ðáñüìïéá, èá ðñÝðåé íá åëÝãîåôå ôï logfile ìå ôá httpd ëÜèç ãéá ôõ÷üí
åíäåßîåéò, üðùò êáé ôá ``Idiot's Guide To Solving Perl / CGI
Problems'' êáé ``Perl CGI Programming FAQ'' ãéá ðåñéóóüôåñåò
ðëçñïöïñßåò. Åßíáé áðßèáíï ôï ðñüâëçìá íá Ý÷åé ó÷Ýóç ìå ôï DBI.
ÄéáâÜóôå êáé ôá äýï áõôÜ êåßìåíá ðñïóåêôéêÜ!
· Ôï ``Idiot's Guide To Solving Perl / CGI Problems'' èá ôï âñåßôå
óôï: <http://www.perl.com/perl/faq/index.html>
[1m11.2.14. Ìðïñþ íá êÜíù multi-threading ìå ôï DBI;[0m
ÌÝ÷ñé ôçí çìåñïìçíßá áõôïý ôïõ FAQ, ü÷é. Ç perl äåí õðïóôçñßæåé
multi-threading. ÐáñüëáõôÜ, ôï multi-threading áíáìÝíåôáé íá ãßíåé
ìÝñïò ôïõ ðõñÞíá ôçò äéáíïìÞò ôçò perl óôçí Ýêäïóç 5.005, ðïõ óçìáßíåé
üôé ôï DBI èá ìðïñåß íá õðïóôçñßæåé multi-threading áñêåôÜ óýíôïìá
ìåôÜ áð' áõôü.
Ãéá íá äåßôå ðáñáäåßãìáôá êþäéêá OCI ãéá ôçí Oracle ðïõ Ý÷åé multi-
threaded åíôïëÝò SELECT, ðçãáßíåôå óôï:
· <http://www.hermetica.com/technologia/oracle/oci/orathreads.tar.gz>
[1m11.2.15. Ðþò ìðïñþ íá êáëÝóù stored procedures ìå ôï DBI;[0m
Áí õðïèÝóïõìå üôé Ý÷åôå äçìéïõñãÞóåé ìéá stored procedure ìÝóá óå
êÜðïéá âÜóç, ð÷, óôçí Oracle, ìðïñåßôå íá ÷ñçóéìïðïéÞóåôå ôï $dbh->do
ãéá íá åêôåëÝóåôå Üìåóá ôç äéáäéêáóßá (procedure). Ãéá ðáñÜäåéãìá,
$dbh->do( "BEGIN someProcedure END" );
[1m11.2.16. Ðþò ìðïñþ íá ðÜñù ôéò ôéìÝò ðïõ åðéóôñÝöïíôáé áðü ôéò stored[0m
[1mprocedures ìå ôï DBI;[0m
Èõìçèåßôå, üìùò, íá êÜíåôå Ýëåã÷ï ãéá ëÜèç!
$sth = $dbh->prepare( "BEGIN foo(:1, :2, :3); END;" );
$sth->bind_param(1, $a);
$sth->bind_param_inout(2, \$path, 2000);
$sth->bind_param_inout(3, \$success, 2000);
$sth->execute;
[1m11.2.17. Ðþò ìðïñþ íá äçìéïõñãÞóù Þ íá êáôáóôñÝøù ìéá âÜóç äåäïìÝíùí[0m
[1mìå ôï DBI;[0m
Ç äçìéïõñãßá êáé äéáãñáöÞ ìéáò âÜóçò åßíáé Ýííïéåò ðïëý áöçñçìÝíåò ãéá
íá õðïóôçñßæïíôáé éêáíïðïéçôéêÜ áðü ôï DBI. Ãéá ðáñÜäåéãìá, ç Oracle
äåí õðïóôçñßæåé êáí ôçí Ýííïéá ôçò äéáãñáöÞò ôçò âÜóçò! Óôçí Oracle
åðßóçò, ï äéáêïìéóôÞò ôçò âÜóçò äåäïìÝíùí (database server) åßíáé
ïõóéáóôéêÜ ç âÜóç, åíþ óôçí mSQL, ç äéåñãáóßá ôïõ äéáêïìéóôÞ (server
process) ôñÝ÷åé ìéá ÷áñÜ ÷ùñßò íá Ý÷åé äçìéïõñãçèåß êáìßá âÜóç óå
áõôüí. Ôï ðñüâëçìá åßíáé ôüóï áíüìïéï ãéá íá ôï èßîïõìå.
Ãé' áõôü ôï ëüãï, ìåñéêïß ïäçãïß õðïóôçñßæïõí äçìéïõñãßá êáé äéáãñáöÞ
âÜóåùí ìÝóù ôùí private func methods. Äåßôå ôçí ôåêìçñßùóç ôùí ïäçãþí
ðïõ ÷ñçóéìïðïéåßôå ãéá íá äåßôå áí õðïóôçñßæïõí áõôü ôï ìç÷áíéóìü.
[1m11.2.18. Ðþò äéá÷åéñßæåôáé ôï DBI ôéò ôéìÝò NULL ;[0m
Ïé ôéìÝò NULL óôï DBI áíôéìåôùðßæïíôáé üðùò ç ôéìÞ undef. Ïé ôéìÝò
NULL ìðïñïýí êáôá÷ùñçèïýí óôéò âÜóåéò ùò NULL, ãéá ðáñÜäåéãìá:
$rv =
$dbh->do( "INSERT INTO table VALUES( NULL )" );
áëëÜ üôáí åñùôçèïýí, ïé ôéìÝò NULL èá ðñÝðåé íá óõãêñéèïýí ìå ôçí
undef. Áõôü åßíáé óôÜíôáñ ãéá üëïõò ôïõò ïäçãïýò.
[1m11.2.19. Ôé åßíáé áõôÝò ïé ìÝèïäïé func (func methods);[0m
Ç ìÝèïäïò func ïñßæåôáé óôï DBI óáí ôï óçìåßï åéóüäïõ ãéá
ëåéôïõñãéêüôçôá åîáñôþìåíç áðü ôç âÜóç, ð÷, ç éêáíüôçôá íá
äçìéïõñãÞóåôå Þ íá äéáãñÜøåôå âÜóåéò. Ôï íá êáëÝóåôå áõôÝò ôéò
ìåèüäïõò ðïõ åîáñôþíôáé áðü ôïõò ïäçãïýò åßíáé áðëü, ãéá ðáñÜäåéãìá,
ãéá íá êáëÝóåôå ôç ìÝèïäï createDatabase ðïõ ðáßñíåé ìéá ðáñÜìåôñï, èá
ãñÜöáìå:
$rv =
$dbh->func( 'argument', 'createDatabase' );
¼óïé áíáðôýóóïõí ëïãéóìéêü èá ðñÝðåé óçìåéþóïõí üôé ïé ìÝèïäïé func
äåí åßíáé ìåôáöÝñóéìåò ìåôáîý äéáöïñåôéêþí âÜóåùí.
[1m11.2.20. ÅìðïñéêÞ ÕðïóôÞñéîç êáé Åêðáßäåõóç[0m
Ôï Interface ôçò Perl5 ãéá âÜóåéò åßíáé Ýíá ÄÙÑÅÁÍ ëïãéóìéêü. ÅÑ×ÅÔÁÉ
×ÙÑÉÓ ÊÁÌÉÁ ÅÃÃÕÇÓÇ ÏÐÏÉÏÕÄÇÐÏÔÅ ÅÉÄÏÕÓ.
ÐáñüëáõôÜ, ìåñéêïß ïñãáíéóìïß ðáñÝ÷ïõí åßôå ôå÷íéêÞ õðïóôÞñéîç åßôå
ðñïãñÜììáôá åêìÜèçóçò ôïõ DBI.
[1mPerl Clinic : [22mÇ Perl Clinic ìðïñåß íá êëåßóåé óõìâüëáéá ãéá åìðïñéêÞ
õðïóôÞñéîç óå Perl, DBI, DBD::Oracle êáé Oraperl. ÕðïóôÞñéîç ðáñÝ÷åôáé
áðü ôçí åôáéñåßá óôçí ïðïßá äïõëåýåé ï Tim Bunce, ï óõããñáöÝáò ôïõ
DBI. Ãéá ðåñéóóüôåñåò õðçñåóßåò ó÷åôéêÜ ìå ôéò õðçñåóßåò ôïõò, äåßôå
ôï :
· <http://www.perl.co.uk/tpc>
[1m12. Åñãáëåßá Äéá÷åßñéóçò ôçò PostgreSQL[0m
[1m12.1. PGACCESS - ¸íá ãñáöéêü åñãáëåßï ãéá ôç äéá÷åßñéóç ôçò Post-[0m
[1mgreSQL[0m
Ôï PgAccess åßíáé Ýíá Tcl/Tk interface ãéá ôçí PostgreSQL.
ÓõìðåñéëáìâÜíåôáé Þäç óôç äéáíïìÞ ôçò PostgreSQL. Ñßîôå ìéá ìáôéÜ óå
áõôü ôï web site ãéá íåüôåñç Ýêäïóç
· <http://www.flex.ro/pgaccess>
· Áí Ý÷åôå ïðïéïäÞðïôå ó÷üëéï, ðñüôáóç ãéá âåëôßùóç, ìç äéóôÜóåôå íá
óôåßëåôå e-mail óôï : teo@flex.ro
×áñáêôçñéóôéêÜ ôïõ PgAccess
ÐáñÜèõñá ôïõ PgAccess : Êåíôñéêü ðáñÜèõñï , äçìéïõñãßá ðéíÜêùí (table
builder) , ÅìöÜíéóç ðéíÜêùí (åñùôÞóåùí) (table(query) view),
äçìéïõñãßá åñùôÞóåùí ïðôéêÜ (visual query builder).
Ðßíáêåò
· - åìöÜíéóç ðéíÜêùí, ìÝãéóôï 200 åããñáöÝò (áëëÜæåé áðü ôï ìåíïý
preferences)
· - áëëáãÞ ìåãÝèïõò óôÞëçò, óÝñíïíôáò ôçí êÜèåôç ãñáììÞ (êáëýôåñá óôï
÷þñï ôïõ ðßíáêá áðü üôé óôçí åðéêåöáëßäá ôïõ ðßíáêá)
· - text wrap óôá êåëéÜ - áðïèÞêåõóç ôçò åìöÜíéóçò êÜèå ðßíáêá
· - import/export óå åîùôåñéêÜ áñ÷åßá (SDF,CSV)
· - äõíáôüôçôåò öéëôñáñßóìáôïò (äþóôå Ýíá ößëôñï óáí price>3.14)
· - äõíáôüôçôåò ôáîéíüìçóçò (äþóôå ÷åéñïêßíçôá ôï(ôá) ðåäßá ðñïò
ôáîéíüìçóç)
· - editing in place
· - âåëôéùìÝíï âïÞèçìá ãéá ðáñáãùãÞ ðéíÜêùí (table generator
assistant)
· - âåëôéùìÝíåò äõíáôüôçôåò äéüñèùóçò ðåäßùí
ÅñùôÞóåéò (Queries)
· - äçìéïõñãåß, äéïñèþíåé êáé áðïèçêåýåé "åñùôÞóåéò ðïõ êáèïñßæåé ï
÷ñÞóôçò"
· - áðïèçêåýåé åñùôÞóåéò óáí views
· - åêôåëåß åñùôÞóåéò
· - åìöÜíéóç áðïôåëåóìÜôùí åñùôÞóåùí ôýðïõ select
· - äéáãñáöÞ êáé áëëáãÞ ïíüìáôïò åñþôçóçò
· - Ãñáöéêü ÷ôßóéìï åñþôçóçò ìå äõíáôüôçôåò drag & drop. Ãéá üóïõò
áðü åóÜò åß÷áôå óôÞóåé ôï Tcl/Tk plugin ãéá ôï Netscape Navigator,
ìðïñåßôå íá ôï äåßôå íá äïõëåýåé ðáôþíôáò åäþ
Sequences
· - äçìéïõñãßá sequences, äéáãñáöÞ êáé Ýëåã÷üò ôïõò ÓõíáñôÞóåéò
· - äçìéïõñãßá, Ýëåã÷ïò êáé äéáãñáöÞ óõíáñôÞóåùí óå ãëþóóá SQL
ÌåëëïíôéêÝò õëïðïéÞóåéò
· - ó÷åäéáóìüò ðéíÜêùí (ðñïóèÞêç íÝùí ðåäßùí, áëëáãÞ ïíüìáôïò, êëð.)
· - êáèïñéóìüò óõíÜñôçóçò
· - äçìéïõñãßá report
· - âáóéêü scripting
Áí Ý÷åôå ïðïéïäÞðïôå ó÷üëéï, ðñüôáóç ãéá âåëôßùóç, ìç äéóôÜóåôå íá
óôåßëåôå e-mail óôï :
· teo@flex.ro
Ðåñéóóüôåñåò ðëçñïöïñßåò ãéá ôç âéâëéïèÞêç libgtcl
Èá ÷ñåéáóôåßôå åðßóçò íá äçëþóåôå ðñïò ÷ñÞóç ôç âéâëéïèÞêç äéáóýíäåóçò
PostgreSQL óå Tcl óáí Ýíá Tcl/Tk 'load'-able module. ÏíïìÜæåôáé
libpgtcl êáé ï ðçãáßïò êþäéêÜò ôçò âñßóêåôáé óôïí êáôÜëïãï ôçò
PostgreSQL /src/interfaces/libpgtcl. Èá ÷ñåéáóôåßôå éäéáßôåñá, ìéá
âéâëéïèÞêç libpgtcl ðïõ íá ìðïñåß íá öïñôùèåß áðü Tcl/Tk. Áõôü åßíáé
äéáöïñåôéêü ôå÷íéêÜ áðü Ýíá ôõðéêü PostgreSQL loadable object áñ÷åßï,
åðåéäÞ ç libpgtcl åßíáé ìéá óõëëïãÞ áðü object áñ÷åßá. ÊÜôù áðü Linux,
ïíïìÜæåôáé libpgtcl.so. Ìðïñåßôå íá êáôåâÜóåôå áðü åäþ ìéá Ýêäïóç Þäç
ìåôáãëùôôéóìÝíç ãéá óõóôÞìáôá Linux i386. ÁðëÜ áíôéãñÜøôå ôï
libpgtcl.so óôïí êáôÜëïãï âéâëéïèçêþí ôïõ óõóôÞìáôïò (/usr/lib)êáé
îåêéíÞóôå. Ìßá ëýóç åßíáé íá áöáéñÝóåôå áðü ôïí ðçãáßï êþäéêá ôç
ãñáììÞ ðïõ ðåñéÝ÷åé ôï öüñôùìá ôçò libpgtcl.so êáé íá öïñôþóåôå ôç
pgaccess.tcl ü÷é ìå wish, áëëÜ ìå pgwish (Þ wishpg) áõôü ôï wish ìå ôï
ïðïßï åß÷å ãßíåé link ìå ôç âéâëéïèÞêç libpgtcl.
[1m12.2. Windows Interactive Query Tool ãéá PostgreSQL (WISQL Þ MPSQL)[0m
Ç MPSQL ðáñÝ÷åé óôïõò ÷ñÞóôåò Ýíá ãñáöéêü SQL interface ãéá ôçí
PostgresSQL. Ç MPSQL åßíáé ðáñüìïéá ìå ôï SQL Worksheet ôçò Oracle
êáé ôï åñãáëåßï åñùôÞóåùí ôïõ Microsoft SQL Server WISQL. ¸÷åé ùñáßï
ãñáöéêü interface êáé éóôïñéêü åíôïëþí. Åðßóçò ìðïñåßôå íá êÜíåôå cut
êáé paste êáé Ý÷åé êáé Üëëá ùñáßá ÷áñáêôçñéóôéêÜ ðïõ âåëôéþíïõí ôçí
ðáñáãùãéêüôçôá.
· <http://www.troubador.com/~keidav/index.html>
· Email: keidav@whidbey.com
· <http://www.ucolick.org/~de/> óôï áñ÷åßï tcl_syb/wisql.html
· <http://www.troubador.com/~keidav/index.html>
· Email: de@ucolick.org
[1m12.3. Interactive Query Tool(ISQL) ãéá ôçí PostgreSQL - ÏíïìÜæåôáé[0m
[1mPSQL[0m
Ôï ISQL åßíáé ãéá ôåñìáôéêÜ ìå Character command line. ÐåñéëáìâÜíåôáé
óôç äéáíïìÞ, êáé ëÝãåôáé PSQL. ÌïéÜæåé ðïëý ìå ôï ISQL ôçò Sybase, êáé
ôï SQLplus ôçò Oracle. Óôï unix prompt äþóôå ôçí åíôïëÞ 'psql' ç ïðïßá
èá óáò âãÜëåé óå psql> prompt.
ÐáôÞóôå \h ãéá íá äåßôå ôç âïÞèåéá ôùí åíôïëþí.
Ðïëý öéëéêü óôï ÷ñÞóôç êáé åýêïëï óôç ÷ñÞóç. Ìðïñåßôå íá Ý÷åôå
ðñüóâáóç óå áõôü êáé áðü scripts ôïõ êÝëõöïõò.
[1m12.4. MPMGR - Åñãáëåßï Äéá÷åßñéóçò ÂÜóåùí ãéá PostgresSQL[0m
Ôï MPMGR ðáñÝ÷åé Ýíá ãñáöéêü interface äéá÷åßñéóçò ôçò PostgresSQL. Èá
ôï âñåßôå óôï
· <www.mutinybaysoftware.com/>
· Email: keidav@mutinybaysoftware.com
· <http://www.troubador.com/~keidav/index.html>
· Email: keidav@whidbey.com
· <http://www.ucolick.org/~de> in file tcl_syb/wisql.html
· WISQL ãéá ôçí PostgreSQL <http://www.ucolick.org/~de/Tcl/pictures>
· Email: de@ucolick.org
[1m13. Ñõèìßæïíôáò ðïëëáðëÜ êïõôéÜ PostgreSQL óå ìéá ïèüíç[0m
Ìðïñåßôå íá óôïéâÜîåôå ôá êïõôéÜ-cpu êáé íá óõíäåèåßôå óå ìéá ïèüíç
êáé íá ÷ñçóéìïðïéÞóåôå ôï äéáêüðôç ãéá íá äéáëÝîåôå ôï host. Áõôü
åîïéêïíïìåß ÷þñï êáé äå ÷ñåéÜæåóôå ðïëëÝò ïèüíåò, ðëçêôñïëüãéá êáé
ðïíôßêéá (åîïéêïíïìåßôå ðåñßðïõ 100 ìå 500 US äïëÜñéá áíÜ óåô) êáé
ãëéôþíåôå åðßóçò áðü ôçí áêáôáóôáóßá.
×ñçóéìïðïéþíôáò áõôÞ ôçí ôå÷íéêÞ, ìðïñåßôå íá óôïéâÜîåôå ðïëëïýò
PostgreSQL servers (ãéá áíÜðôõîç, Ýëåã÷ï, ðáñáãùãÞ), Web servers, ftp
servers, Intranet servers, Mail servers, News servers óå Ýíá ðïëý øçëü
ñÜöé. Ï äéáêüðôçò ìðïñåß íá ÷ñçóéìïðïéçèåß åðßóçò ãéá êïõôéÜ ìå
Windows 95/NT Þ OS/2.
Ñßîôå ìéá ìáôéÜ óôá ðáñáêÜôù sites:
· ÔçëåöùíéêÝò ðáñáããåëßåò áðü ôçí DataComm Warehouse Inc, óå 24ùñç
âÜóç, üëç ôçí åâäïìÜäá, óôï 1-800-328-2261. ÐáñÝ÷ïõí êÜèå ôýðï
õëéêïý Ç/Õ <http://www.warehouse.com>. Ôï 4-èõñï KVM switch
(PS/2) êïóôßæåé ãýñù óôá $89.99. Part No. DDS1354
· Network Technologies Inc
<http://www.networktechinc.com/servswt.html> (120 äïëÜñéá/PC 8
ports) ôï ïðïßï Ý÷åé ëßóôåò ãéá 'Server Switches' êáé 'switches
ìüíï ãéá Video '
· Scene Double Inc, Áããëßá
<http://www.scene.demon.co.uk/qswitch.htm>
· Cybex corporation <http://www.cybex.com>
· Raritan Inc <http://www.raritan.com>
· RealStar Solutions Inc <http://www.real-star.com/kvm.htm>
· Belkin Inc <http://www.belkin.com>
· Better Box Communications Ltd.
<http://www.betterbox.com/info.html>
· Ðçãáßíåôå óôï ðëçóéÝóôåñï ìáãáæß hardware êáé æçôÞóôå ôï "Server
Switch" ãíùóôü êáé óáí "KVM Auto Switches".
ØÜîôå óôç ìç÷áíÞ áíáæÞôçóçò yahoo ãéá íá âñåßôå ðåñéóóüôåñåò åôáéñåßåò
ìå "Server Switches" Þ "KVM Switches".
Óõíßóôáôáé éäéáßôåñá íá Ý÷åôå Ýíá unix box åéäéêÜ áöéåñùìÝíï ãéá êÜèå
PostgreSQL data-server ãéá êáëýôåñç áðüäïóç. Êáìßá Üëëç
åöáñìïãÞ/äéåñãáóßá äåí ðñÝðåé íá ôñÝ÷åé óå áõôü ôï ìç÷Üíçìá. Äåßôå ôï
ôìÞìá "ÅðáããåëìáôéêÜ" óôéò ôïðéêÝò åöçìåñßäåò ãéá ôïðéêïýò ðùëçôÝò ðïõ
ðùëïýí ìüíï êïõôéÜ intel, 13" ìïíü÷ñùìåò ïèüíåò (ïèüíç ðïëý ÷áìçëïý
êüóôïõò). Ïé ôïðéêïß ðùëçôÝò ðùëïýí ìüíï ôï hardware [1m÷ùñßò [22mMicrosoft
Windows/DOS (Ýôóé åîïéêïíïìåßôå $ 150). Äå ÷ñåéÜæåóôå Ýã÷ñùìç ïèüíç
ãéá ôï äéáêïìéóôÞ ôçò âÜóçò äåäïìÝíùí, êáèþò ìðïñåßôå íá êÜíåôå
áðïìáêñõóìÝíç äéá÷åßñéóç (remote administration) áðü Ýã÷ñùìï óôáèìü
åñãáóßáò. ÐÜñôå ôï RedHat (Þ êÜðïéá Üëëç äéáíïìÞ) Linux cdrom áðü ôï
-
· Linux System Labs Web site: <http://www.lsl.com/> 7 (U.S.
äïëÜñéá)
· Cheap Bytes Inc Web site: <http://www.cheapbytes.com/> 7 (U.S.
äïëÜñéá)
Óéãïõñåõôåßôå üôé ôï õëéêü ðïõ áãïñÜóáôå õðïóôçñßæåôáé áðü ôï
Redhat Linux. Äåßôå ôï ftp site çò Redhat ðñéí áãïñÜóåôå õëéêü, ãéá
ðñïôåéíüìåíïõò SCSI adapters, êÜñôåò âßíôåï êëð. Ìå $ 600 ìüíï
ìðïñåßôå íá ðÜñåôå Ýíá éó÷õñü êïõôß intel ìå Redhat Linux ðïõ
ôñÝ÷åé PostgreSQL. ×ñçóéìïðïéÞóôå odbc/jdbc/perl/tcl ãéá íá
óõíäåèåßôå ìå ôçí PostgreSQL áðü Windows95, OS/2, Unix Motif Þ
êÜðïéï web browser (ð.÷. Redbaron, Opera, Netscape, 20 Üëëïé). (ïé
Web browsers Ý÷ïõí ãßíåé ðéá standard client).
Ìå áõôÞ ôçí éäÝá ìðïñåßôå íá åëÝã÷åôå ðïëëÜ êïõôéÜ cpu ìå ìéá ïèüíç
êáé Ýíá ðëçêôñïëüãéï!
ÐáñáêÜôù èá âñåßôå Ýíá [1máðüóðáóìá áðü ôçí networktechnic Inc [22mãéá
"Server Switches"
Ðáñáããåßëåôå ôþñá óôï 800-742-8324 (÷ùñßò äáóìïýò ãéá ÁìåñéêÞ)
Ãéá íá ëÜâåôå ôïí êáôÜëïãü ìáò ðáñáêáëþ óôåßëôå Email óôç äéåýèõíóç:
sales@networktechinc.com
×ÅÉÑÉÓÔÅÉÔÅ ÐÅÑÉÓÓÏÔÅÑÁ ÁÐÏ ÅÍÁ PC ìå Ýíá ðëçêôñïëüãéï, ïèüíç êáé
ðïíôßêé Ïé çëåêôñïíéêïß äéáêüðôåò åðéôñÝðïõí ìå Ýíá ðëçêôñïëüãéï,
ïèüíç êáé ðïíôßêé íá ÷åéñéóèåßôå 64 PC. ÅíóùìáôùìÝíïé ìéêñïûðïëïãéóôÝò
ðñïóïìïéþíïõí ôçí ðáñïõóßá ðëçêôñïëïãßïõ, ïèüíçò êáé ðïíôéêéïý ìå üëá
ôá ðñïóáñôçìÝíá PC 100% ôïõ ÷ñüíïõ.
×áñáêôçñéóôéêÜ êáé ÅöáñìïãÝò
· Ðëçêôñïëüãéï, ÷åéñéóôÞñéï ðÜíù óôç óõóêåõÞ Þ ôçëå÷åéñéóôÞñéï
· 9 pin D Serial Þ 6 pin miniDIN õðïóôÞñéîç ãéá ðïíôßêé
· 5 pin DIN Þ 6 pin miniDIN õðïóôÞñéîç ðëçêôñïëïãßïõ
· 1600x1200 áíÜëõóç ïèüíçò
· ×ñçóéìïðïéåß êïéíÜ êáëþäéá
· Óå Desktop êüøéìï Þ êáé ãéá rack
ÐñïäéáãñáöÝò - Ðëçêôñïëüãéï
· ¼ëá ôá âýóìáôá åßíáé èçëõêÜ
· 5 pin DIN Þ 6 pin miniDIN
· Ìðïñåß íá åêêéíåß ïðïéáäÞðïôå óôéãìÞ ïðïéïíäÞðïôå Ç/Õ
×åéñéóôÞñéï - ÌðñïóôéíÜ ÊïõìðéÜ
· Óõíäåèåßôå óå Ýíáí Ç/Õ ìå ôï ðÜôçìá åíüò êïõìðéïý
· ÊñáôÞóôå ðáôçìÝíï ïðïéïäÞðïôå êïõìðß ãéá ðåñéóóüôåñï áðü ìéóü
äåõôåñüëåðôï êáé ìðåßôå óå ôñüðï ëåéôïõñãßáò SCAN, BROADCAST Þ
COMMAND
· Ôá LEDs õðïäåéêíýïõí ôïí ôñüðï ëåéôïõñãßáò ôïõ ðëçêôñïëïãßïõ
· ÐáôÞóôå CTRL+* êáé ìðåßôå óå ôñüðï ëåéôïõñãßáò COMMAND
· Åßíáé äéáèÝóéìïé ïé SCAN, BROADCAST êáé COMMAND ôñüðïé ëåéôïõñãßáò
Ðïíôßêé
* 9 pin D serial
· o äéáêüðôçò NTI ðïõ ðñïóïìïéþíåé ôï óåéñéáêü ðïíôßêé ôçò Microsoft
· o 9 pin D áñóåíéêü ãéá ðïíôßêé
· o 9 pin D èçëõêü ãéá ôïõò Ç/Õ
* 6 pin miniDIN
· o äéáêüðôçò NTI ðïõ ðñïóïìïéþíåé ôï ðïíôßêé IBM PS/2
· o ¼ëá ôá âýóìáôá åßíáé èçëõêÜ
Êáëùäéáêü ÷åéñéóôÞñéï/ôçëåêïíôñüë
· Ðñïáéñåôéêü --èá ðñÝðåé íá áãïñáóôåß îå÷ùñéóôÜ
· ÊÜíåé ôéò äïõëåßåò ôïõ "×åéñéóôçñßïõ - Ìðñïóôéíþí Êïõìðéþí"
Ïèüíç-VGA
· Åýñïò 150 MHz
· 1600X1200 áíÜëõóç ÷ùñßò ðáñáìüñöùóç
· 1/4ëá ôá âýóìáôá åßíáé èçëõêÜ
[1m14. ÅöáñìïãÝò êáé Åñãáëåßá ãéá ôçí PostgreSQL[0m
[1m14.1. Ãëþóóá 4çò ãåíéÜò (4GL) PostgreSQL ãéá åöáñìïãÝò ìå web êáé[0m
[1mâÜóç äåäïìÝíùí - Ðëáôöüñìá áíÜðôõîçò AppGEN[0m
Ôï AppGEN ìðïñåßôå íá ôï êáôåâÜóåôå áðü ôï
· <http://www.man.ac.uk/~whaley/ag/appgen.html>
· <ftp://ftp.mcc.ac.uk/pub/linux/ALPHA/AppGEN>.
Ôï AppGEN åßíáé ìéá õøçëïý åðéðÝäïõ, ôÝôáñôçò ãåíéÜò ãëþóóá êáé
ðëáôöüñìá áíÜðôõîçò åöáñìïãþí ãéá ôçí ðáñáãùãÞ åöáñìïãþí âáóéóìÝíùí
óôï World Wide Web (WWW). ÁõôÝò ïé åöáñìïãÝò ôõðéêÜ ÷ñçóéìïðïéïýíôáé
óôï internet Þ óôï intranet åíüò ïñãáíéóìïý. Ïé åöáñìïãÝò ôïõ AppGEN
õëïðïéïýíôáé ùò C scripts ðïõ áêïëïõèïýí ôá ðñüôõðá ôïõ Common Gateway
Interface (CGI), ôá ïðïßá õðïóôçñßæïíôáé áðü ôïõò ðåñéóóüôåñïõò Web
Servers.
Ãéá íá ÷ñçóéìïðïéÞóåôå ôï AppGEN èá ÷ñåéáóôåßôå ôá áêüëïõèá :-
Ôçí PostgresSQL, óýóôçìá äéá÷åßñéóçò ó÷åóéáêþí âÜóåùí äåäïìÝíùí
¸íáí web server ðïõ íá õðïóôçñßæåé CGI üðùò ï HTTPD ôïõ NSCA
¸íáí ìåôáãëùôôéóôÞ ansi C üðùò ï GCC
Ôï AppGEN áðïôåëåßôáé áðü ôá áêüëïõèá åêôåëÝóéìá ãéá Unix (Linux) :-
· defgen, ôï ïðïßï ðáñÜãåé ìéá âáóéêÞ ðñüôõðç åöáñìïãÞ (template
application) áðü êÜðïéåò ëïãéêÝò äïìÝò äåäïìÝíùí. Ïé åöáñìïãÝò
ìðïñïýí íá åéóÜãïõí, åíçìåñþíïõí, äéáãñÜöïõí êáé øÜ÷íïõí åããñáöÝò
óôçí âÜóç äåäïìÝíùí åíþ ðáñÜëëçëá äéáôçñïýí áõôüìáôá êáé ôçí
áêåñáéüôçôá ôùí äåäïìÝíùí (referential integrity).
· appgen, ï ìåôáãëùôôéóôÞò AppGEN ðïõ ìåôáãëùôôßæåé êþäéêá appgen óå
åêôåëÝóéìï CGI C êþäéêá êáé êåßìåíá HTML Ýôïéìá ãéá ÷ñÞóç óå Ýíáí
web server.
· dbf2sql, ìéá åöáñìïãÞ ãéá ìåôáôñïðÞ áñ÷åßùí óõìâáôþí ìå dBase III
.dbf óå åêôåëÝóéìá SQL scripts. Áõôü åðéôñÝðåé óå äåäïìÝíá ðïõ
öõëÜóóïíôáé óôá ðåñéóóüôåñá ðáêÝôá âÜóåùí äåäïìÝíùí ãéá DOS/Windows
íá ìåôáöåñèïýí óå Ýíáí SQL server üðùò ç PostgresSQL.
· ÅðéðëÝïí, ôï AppGEN ðáñÝ÷åé ìéá óõëëïãÞ áðü êåßìåíá HTML , áñ÷åßá
GIF êáé Java applets ðïõ ÷ñçóéìïðïéïýíôáé áðü ôï óýóôçìá, êáé
öõóéêÜ, üðùò êÜèå êáëü ëïãéóìéêü, óõìðåñéëáìâÜíåé êáé ôïí ðëÞñç
ðçãáßï êþäéêá.
Ìðïñåßôå íá åðéêïéíùíÞóåôå ìå ôïí óõããñáöÝá, Andrew Whaley, óôï
· andrew@arthur.smuht.nwest.nhs.uk
[1m14.2. WWW Web interface ãéá PostgresSQL - DBENGINE[0m
Ôï dbengine åßíáé Ýíá plug 'n play Web interface ãéá ôçí PostgreSQL
ðïõ äçìéïõñãÞèçêå áðü ôïí Ingo Ciechowski. Âñßóêåôáé óôï :
· <http://www.cis-computer.com/dbengine/ >
[1mÓ÷åôéêÜ ìå ôï DBENGINE : [22mÔï dbengine åßíáé Ýíá interface äéáóýíäåóçò
WWW êáé Postgres95 ðïõ ðáñÝ÷åé áðëÞ ðñüóâáóç óå ïðïéáäÞðïôå âÜóç ìÝóá
óå ëßãá ëåðôÜ.
Ôï PHP 3 äßíåé ìéá ãëþóóá ðïõ ìïéÜæåé ìå ôçí Perl óôá êåßìåíÜ óáò,
áëëÜ ü÷é ðñáãìáôéêÞ Perl åíþ ôï AppGen êáé ôï wdb-p95 áðáéôïýí íá
äçìéïõñãÞóåôå ìåñéêÜ áñ÷åßá ñõèìßóåùí ãéá êÜèå ìßá áðü ôéò âÜóåéò óáò
-- ìïéÜæåé óáí íá ðñÝðåé ðñþôá áð' üëá íá ìÜèåôå êÜðïéï åßäïò íÝáò
ãëþóóáò ðñéí íá îåêéíÞóåôå.
Áíôßèåôá ìå ôá Üëëá åñãáëåßá, äåí áðáéôåßôáé íá ìÜèåôå åéäéêü
ðñïãñáììáôéóìü Þ êÜðïéá scripting language ãéá íá îåêéíÞóåôå íá
äïõëåýåôå ìå ôï dbengine. Äåí õðÜñ÷åé åðßóçò êÜðïéï áñ÷åßï ñõèìßóåùí
ãéá êÜèå âÜóç, Ýôóé äå ÷ñåéÜæåôáé íá åîïéêåéùèåßôå ìå ìéá íÝá äïìÞ.
ÐáñüëáõôÜ - óå ðåñßðôùóç ðïõ èÝëåôå íá Ý÷åôå ðñüóâáóç óå üëá ôá
÷áñáêôçñéóôéêÜ ôïõ dbengine èá Þôáí êáëÞ éäÝá íá ìÜèåôå ôç ãëþóóá
Perl.
Ïëï ôï óýóôçìá ìðïñåß íá ñõèìéóôåß ìÝóù áðëþí ÷åéñéóìþí óå ìéá
ðñüóèåôç âÜóç äåäïìÝíùí ðïõ ðåñéÝ÷åé ðëçñïöïñßåò ó÷åôéêÜ ìå ôï ðþò íá
ïðôéêïðïéÞóåôå ôá äåäïìÝíá óáò. Ìðïñåßôå åðßóçò íá ïñßóåôå virtual
Fields ôá ïðïßá õðïëïãßæïíôáé áìÝóùò ðñéí íá åìöáíéóôïýí óôçí ïèüíç.
[1m¶äåéá [22mÔï dbengine åßíáé äùñåÜí ëïãéóìéêü êÜôù áðü ôïõò ßäéïõò üñïõò
üðùò êáé ç Perl. ÄéáâÜóôå ôçí ÜäåéÜ ôçò áí äåí åßóôå óßãïõñïé ãéá ôé
ìðïñåßôå Þ äåí ìðïñåßôå íá êÜíåôå. Óå ôåëéêÞ áíÜëõóç, áõôÞ åßíáé ìéá
åëáóôéêüôåñç êáé ðéï Þðéá Ýêäïóç áðü ôçí GNU Üäåéá -- äåí åðçñåÜæåé ôç
äïõëåéÜ óáò áí èÝëåôå íá "äáíåéóôåßôå" êÜôé áðü ôï dbengine Þ íá
óõãêåíôñþóåôå êïììÜôéá áðü áõôü óáí ìÝñïò åíüò åìðïñéêïý ðñïúüíôïò!
[1m14.3. Apache Webserver Module ãéá PostgreSQL - NeoSoft NeoWebScript[0m
Ï Apache åßíáé Ýíáò ðïëý ãíùóôüò Web Server. ¸íá module äéáóýíäåóçò
PostgreSQL ìå ôïí Apache Webserver âñßóêåôáé óôï -
· <http://www.neosoft.com/neowebscript/>
Ôï NeoWebScript åßíáé ìéá ãëþóóá ðñïãñáììáôéóìïý ðïõ åðéôñÝðåé êáé
áðëÜ êáé óýíèåôá ðñïãñÜììáôá íá åíóùìáôùèïýí óå áñ÷åßá HTML.
¼ôáí æçôåßôáé ìéá óåëßäá HTML ðïõ ðåñéÝ÷åé åíóùìáôùìÝíï êþäéêá
NeoWebScript, ï webserver ðïõ õðïóôçñßæåé NeoWebScript åêôåëåß ôï(á)
åíóùìáôùìÝíá script(s), êáé ðáñÜãåé ìéá web óåëßäá ìå ðåñéå÷üìåíï
êïììÝíï êáé ñáììÝíï óôéò ðñïôéìÞóåéò ôïõ ðñïãñáììáôéóôÞ, ç ïðïßá
äçìéïõñãÞèçêå ìå áõôü ôï ðñüãñáììá.
Ôï NeoWebScript åßíáé Ýíáò ãñÞãïñïò, áóöáëÞò, åýêïëïò ôñüðïò ãéá íá
ìÜèåôå éó÷õñü, server-based ðñïãñáììáôéóìü óôïí êþäéêá HTML ôùí web
óåëßäùí. Ìå ôï NeoWebScript, åßíáé åýêïëï íá öôéÜîåôå ìåôñçôÝò
(counters), öüñìåò ãéá email, ãêñÜöéôé óôéò óåëßäåò, guest books êáé
íá êñáôÜôå óôïé÷åßá ãéá ôïõò åðéóêÝðôåò, áêüìç êáé ãéá Ýíáí áñ÷Üñéï
ðñïãñáììáôéóôÞ. Äåßôå ðüóï êáëÜ ôï NeoWebScript êñáôÜ ôá äéêÜ ôïõ óå
óýãêñéóç ìå ôçí PERL êáé ôï JavaScript.
Áí èÝëåôå íá åãêáôáóôÞóåôå ôï NeoWebScript óôïí webserver óáò, ï
Webmaster óáò ðñÝðåé íá äéáâÜóåé ôï Sysop FAQ ãéá íá îåêéíÞóåé. Ç
"Èåùñßá ôùí Ëåéôïõñãéþí" (Theory of Operations) èá åîçãÞóåé ðþò
äïõëåýåé ôï NeoWebScript, åíþ ç åãêáôÜóôáóç èá óáò êáèïäçãÞóåé óôá
äéÜöïñá óôÜäéÜ ôçò. Ç äéá÷åßñéóç áó÷ïëåßôáé ìå èÝìáôá ñýèìéóçò êáé
åêôÝëåóçò ôïõ server, äéÜöïñïé Ýëåã÷ïé åðáëçèåýïõí ôç óùóôÞ ëåéôïõñãßá
ôùí NeoWebScript óáò êáé ç áðïóöáëìÜôùóç áó÷ïëåßôáé ìå ôá ðñïâëÞìáôá
ôïõ server.
Äåí õðÜñ÷åé êáíÝíá êüóôïò ãéá ôç ÷ñÞóç ôïõ NeoWebScript-2.2 ãéá ôïí
ISP óáò, ôï intranet óáò Þ ôï extranet óáò. Èá äåßôå ôçí ðëÞñç Üäåéá
÷ñÞóçò, üôáí åããñáöåßôå ãéá íá ôï êáôåâÜóåôå, áëëÜ ç ïõóßá åßíáé ðùò
èá èÝëáìå 99 óðáñôáñéóôÜ äïëÜñéá áí èÝëåôå íá ôï åíóùìáôþóåôå óôá äéêÜ
óáò ðñïúüíôá Þ íá ôï ÷ñçóéìïðïéÞóåôå óå Ýíáí server åìðïñéêþí
óõíäéáëëáãþí (ð.÷. SSL).
Ôï NeoWebScript åßíáé Ýíá module ãéá ôïí Apache webserver ðïõ óáò
åðéôñÝðåé ôçí åíóùìÜôùóç ôçò ãëþóóáò ðñïãñáììáôéóìïý Tcl/Tk óôéò
éóôïóåëßäåò óáò óáí Ýíá åñãáëåßï scripting. ÅðéíïÞèçêå áðü ôïí Karl
Lehenbauer, ôïí Ôå÷íéêü ÄéåõèõíôÞ ôçò NeoSoft, êáé ôåêìçñéþèçêå,
åìðëïõôßóôçêå êáé åðåêôÜèçêå áðü ôïõò ðñïãñáììáôéóôÝò êáé ôå÷íéêïýò
óõããñáöåßò ôçò NeoSoft.
Ï Apache webserver åßíáé ï ðëÝïí äçìïöéëÞò webserver óôïí êüóìï,
÷ñçóéìïðïéïýìåíïò óôï 68 % ôùí sites ðïõ åîåôÜóôçêáí.
Ç Tcl/Tk åßíáé ç ðáíßó÷õñç, äùñåÜí, áíåîÜñôçôç ðëáôöüñìáò ãëþóóá
scripting, ðïõ áíáðôý÷èçêå áðü ôïí Äñ. John Ousterhout. ÐáñáèÝôïõìå ôá
ëüãéá ôïõ
"Ç Tcl/Tk åðéôñÝðåé óôïõò ðñïãñáììáôéóôÝò ëïãéóìéêïý íá êÜíïõí ôçí
äïõëåéÜ äÝêá öïñÝò ôá÷ýôåñá áðü üôé ÷ñçóéìïðïéþíôáò åñãáëåéïèÞêåò
(toolkits) âáóéóìÝíåò óå C Þ C++. Åßíáé åðßóçò ìéá ôÝëåéá ãëþóóá
åíóùìÜôùóçò Þäç õðáñ÷üíôùí åöáñìïãþí ðïõ ôéò êÜíåé ðéï ãñáöéêÝò êáé
ôéò åîïðëßæåé ìå Internet-éêÝò äõíáôüôçôåò".
Ï Karl Lehenbauer, ÉäñõôÞò êáé ÐñïúóôÜìåíïò ôïõ Ôå÷íéêïý ÔìÞìáôïò ôçò
NeoSoft, áðïôåëåß ìÝñïò ôçò áíÜðôõîçò ôçò Tcl/Tk áðü ôá ðñþôá ôçò
óôÜäéá. Ìáæß ìå ôïí Mark Diehkans, äçìéïýñãçóáí ôçí Extended Tcl,
ãíùóôÞ åðßóçò êáé ùò TclX Þ NeoSoft Tcl, Ýíá éó÷õñü óýíïëï åðåêôÜóåùí
óôç ãëþóóá. ÐïëëÝò áðü ôéò âáóéêÝò åíôïëÝò ôçò Tcl ðñïÝêõøáí áðü ôçí
Extended Tcl, êáé ìåôÜ åéóÞ÷èçóáí áðü ôïí Dr. Ousterhout óôï âáóéêü
ðõñÞíá ôçò ãëþóóáò.
NeoSoft Inc., 1770 St. James Place, Suite 500, Houston, TX 77056 USA
[1m14.4. ãéá ôçí PostgreSQL Ïé HEITML åðåêôÜóåéò ôçò HTML óôïí server[0m
[1mêáé ìéá ãëþóóá 4çò ãåíéÜò[0m
Ôï åñãáëåßï heitml åßíáé Ýíáò Üëëïò ôñüðïò ãéá íá åðéêïéíùíåß ç
postgres ìå ôï world wide web. Ãéá ðåñéóóüôåñåò ðëçñïöïñßåò
åðéêïéíùíÞóôå ìå ôïí
Helmut Emmelmann H.E.I. Informationssyteme GmbH
Wimpfenerstrasse 23 Ôçë. 49-621-795141
68259 Mannheim Germany Öáî. 49-621-795161
· Óôåßëôå email óôïí Ê. Helmut Emmelmann óôï emmel@h-e-i.de
· Ç êýñéá óåëßäá ôïõ Heitml <http://www.heitml.com>
· Ç äåõôåñåýïõóá óåëßäá ôïõ Heitml <http://www.h-e-i.deom>
Ôï heitml åßíáé åðåêôÜóåéò ôçò HTML óôçí ðëåõñÜ ôïõ server êáé
ôáõôü÷ñïíá ãëþóóá 4çò ãåíéÜò. Ìðïñåßôå íá ãñÜøåôå åöáñìïãÝò ãéá ôï web
óå óôõë HTML ÷ñçóéìïðïéþíôáò HTML-ïåéäÞ tags.
Ôï heitml (ðñïöÝñåôå "×áú"-ÔéÅìÅë) åßíáé åðÝêôáóç ôïõ HTML êáé ìéá
ðëÞñùò åîïðëéóìÝíç ãëþóóá 4çò ãåíéÜò ðïõ åðéôñÝðåé óå åöáñìïãÝò Web íá
áëëçëåðéäñïýí ìå äåäïìÝíá ðïõ öõëÜóóïíôáé óå SQL âÜóåéò, ÷ùñßò íá
êáôáöåýãïõí óå ðåñßðëïêá CGI scripts.
Ôï heitml åðåêôåßíåé ôï HTML óôçí ðëåõñÜ ôïõ server, ìåôáôñÝðïíôáò
äõíáìéêÜ áñ÷åßá ".hei" óå HTML êáé åßíáé ëïéðüí óõìâáôü ìå êÜèå web
browser. ×ñçóéìïðïéåß ôçí ãíþñéìç, åý÷ñçóôç óýíôáîç HTML êáé ðáñÝ÷åé
ðëïýôï ðñïêáôáóêåõáóìÝíùí Tags êáé Âéâëéïèçêþí ãéá íá ëýóïõí èÝìáôá
ðïõ ìÝ÷ñé ôþñá ÷ñåéÜæïíôáí CGI. ¼ðùò êáé ôï XML, ôï heitml ðáñÝ÷åé
tags ïñéóìÝíá áðü ôïí ÷ñÞóôç. Ìå ôï heitml ôá ïñéóìÝíá áðü ôïí ÷ñÞóôç
tags ìåôáôñÝðïíôáé óå HTML êáé óôÝëíïíôáé óôïí browser.
Ôï heitml óôï÷åýåé êáé óôïõò ó÷åäéáóôÝò HTML êáé óôïõò åðáããåëìáôßåò
ðñïãñáììáôéóôÝò. Ïé ó÷åäéáóôÝò HTML ìðïñïýí íá ÷ñçóéìïðïéïýí heitml
Tags ãéá íá ÷ôéóôïýí äõíáìéêÝò óåëßäåò web, íá ðñïóðåëáýíïõí SQL
âÜóåéò, Þ íá äçìéïõñãïýí óýíèåôåò åöáñìïãÝò web. ÌåôñçôÝò, âÜóåéò ìå
óôïé÷åßá êáôá÷þñçóçò, öüñìåò áíáæÞôçóçò, öüñìåò email , éåñáñ÷éêÜ
ìåíïý, üëá ìðïñïýí íá êáôáóêåõáóôïýí áðëÜ ÷ñçóéìïðïéþíôáò
ðñïêáèïñéóìÝíá HTML-ïåéäÞ Tags ðïõ âñßóêïíôáé óôéò äéÜöïñåò
ÂéâëéïèÞêåò.
Ãéá ôïõò ðñïãñáììáôéóôÝò, ôï heitml åíóùìáôþíåé ìéá ðëÞñç ãëþóóá 4çò
ãåíéÜò óå HTML
(ð.÷. <if>, <while>, êáé <let> Tags),
óõí éó÷õñÝò äõíáôüôçôåò õðïëïãéóìïý åêöñÜóåùí ìå áêåñáßïõò,
ðñáãìáôéêïýò, äõáäéêïýò, áëöáñéèìçôéêïýò, tuples ôåëåóôÝò. Ôá Tuples
áíôéìåôùðßæïíôáé üðùò óôéò ìïíôÝñíåò áíôéêåéìåíïóôñáöåßò ãëþóóåò êáé
öõëÜóóïíôáé óå ìåôáâëçôÝò óùñþí (heap variable). Ïé ìåôáâëçôÝò ôçò
heitml, óõìðåñéëáìâáíïìÝíùí êáé üëùí ôùí óýíèåôùí äïìþí äåäïìÝíùí,
öõëÜóóïíôáé óôï óùñü äéáôçñþíôáò ôéò áñ÷éêÝò ôïõò ôéìÝò ìåôáîý ôùí
óåëßäùí ÷ñçóéìïðïéþíôáò ôï Session Mode. Åßíáé äõíáôüí íá ïñßóåôå ôá
äéêÜ óáò tags Þ tags ôïõ ðåñéâÜëëïíôïò êáé áêüìá êáé íá åðáíïñßóåôå ôá
HTML-tags.
Ôï heitml êÜíåé äõíáôü ôï íá
- - - áíáðôõ÷èïýí Web Sites ìå Ýíá äïìçìÝíï êáé óðïíäõëùôü ôñüðï, þóôå
íá ìåéùèåß äñáóôéêÜ ç êáèõóôÝñçóç ëüãù óõíôÞñçóçò.
- - - áíáðôõ÷èïýí Ýîõðíá êáé áëëçëåðéäñáóôéêÜ Web Sites, ìå
ðåñéå÷üìåíï ðïõ ðñïóáñìüæåôáé äõíáìéêÜ óôéò áíÜãêåò ôïõ ÷ñÞóôç.
- - - åìöáíßóåôå ôï ðåñéå÷üìåíï SQL âÜóåùí ÷ùñßò íá ÷ñåéáóôåß êáèüëïõ
ðñïãñáììáôéóìüò åêôüò áðü ôï íá ÷ñçóéìïðïéÞóåôå ôç âéâëéïèÞêç ìáò ôùí
ðñïêáèïñéóìÝíùí "dba" Tags.
- - - áíáðôõ÷èïýí åöáñìïãÝò óýíèåôùí âÜóåùí äåäïìÝíùí êáé êáôáëüãùí
áãïñþí ÷ñçóéìïðïéþíôáò ôéò Session Variables
Ôï heitml ôñÝ÷åé óå Linux ìå ïðïéïíäÞðïôå Web Server ðïõ ÷ñçóéìïðïéåß
CGI interface, êáé åßíáé éäéáßôåñá ãñÞãïñï (áðïöåýãïíôáò ôçí
êáèõóôÝñçóç ëüãù CGI) ìå ôïí APACHE Web Server ÷ñçóéìïðïéþíôáò ôï
Apache API. ÌÝ÷ñé ôþñá õðïóôçñßæïíôáé ïé âÜóåéò MSQL (Ýêäïóç 1 êáé 2),
PostgreSQL (Ýêäïóç 6), mysql, êáé ç yard. Ôï heitml äïõëåýåé åðßóçò óå
Linux, BSDi, Solaris êáé SunOS, êáèþò êáé óå Windows NT ìå CGI êáé
ISAPI êáé ODBC êáé Windows 95.
Ôï heitml (óå linux) åßíáé äùñåÜí ãéá åñåõíçôéêÞ, ìç-åìðïñéêÞ êáé
éäéùôéêÞ ÷ñÞóç. Ôá åìðïñéêÜ Web Sites ðñÝðåé íá ðëçñþóïõí ôÝëç ãéá ôçí
Üäåéá ÷ñÞóçò. Ç ðëÞñçò ëåéôïõñãéêÞ Ýêäïóç ôïõ heitml åßíáé äéáèÝóéìç
íá ôçí êáôåâÜóåôå ãéá ìéá ðåñßïäï äïêéìÞò äùñåÜí. (Óçìåéþóôå,
ðáñüëáõôÜ, üôé êÜèå Web óåëßäá ".hei" ðïõ áíáðôýóóåôå èá åìöáíßæåé Ýíá
ìÞíõìá ðïõ èá ôï ÷áñáêôçñßæåé óáí Ýêäïóç ãéá ìç åìðïñéêÞ ÷ñÞóç. ÌåôÜ
ôçí åããñáöÞ, èá ëÜâåôå Ýíá êëåéäß ãéá íá åîáöáíßóåôå áõôü ôï ìÞíõìá
÷ùñßò íá ÷ñåéáóôåß íá åðáíåãêáôáóôÞóåôå ôï ðñüãñáììá.)
Ôï heitml (ðñïöÝñåôáé "×áú"-ÔéÅìÅë) åðåêôåßíåé êáé åìðëïõôßæåé
óçìáíôéêÜ ôç ëåéôïõñãéêüôçôá ôçò HTML ìå ôïí ïñéóìü tags êáé
÷áñáêôçñéóôéêÜ ðëÞñåò ðñïãñáììáôéóìïý. Áõôü êÜíåé äõíáôÞ ôçí ýðáñîç
åöáñìïãþí äõíáìéêïý ðåñéå÷ïìÝíïõ êáé âÜóåùí äåäïìÝíùí ìÝóá óôïí êüóìï
ôçò HTML, ÷ùñßò CGI êáé åîùôåñéêü scripting Þ Üëëåò ãëþóóåò
ðñïãñáììáôéóìïý. Áõôü óçìáßíåé üôé åóåßò, óáí óõããñáöÝáò HTML,
ìðïñåßôå íá ðñïóèÝóåôå åöáñìïãÝò óôéò web óåëßäåò óáò, ÷ñçóéìïðïéþíôáò
áðëÜ ìåñéêÜ íÝá tags ÷ùñßò CGI êáé êáèüëïõ ðñïãñáììáôéóìü. Áðü ôçí
Üëëç, óáí ðñï÷ùñçìÝíïò ÷ñÞóôçò Þ ðñïãñáììáôéóôÞò ìðïñåßôå íá
äçìéïõñãÞóåôå éó÷õñÝò ðñïãñáììáôéóôéêÝò âéâëéïèÞêåò ìå tag. ÁõôÞ ç
ðñïóÝããéóç êÜíåé ôï heitml êáôÜëëçëï ôüóï ãéá ôïõò íåüöåñôïõò óôçí
HTML üóï êáé ãéá ôïõò åðáããåëìáôßåò ðñïãñáììáôéóôÝò. Ôï heitml ôñÝ÷åé
óôï web server êáé äçìéïõñãåß äõíáìéêÜ HTML, Ýôóé þóôå ôï heitml íá
åßíáé óõìâáôü ìå ôá óôÜíôáñ ôïõ internet êáé ìå ïðïéïäÞðïôå web
browser. ÅðéôñÝðåé ðëÞñç ðñüóâáóç óå âÜóåéò åíþ ðñïóôáôåýåé ôï ÷ñÞóôç
áðü ôçí ðåñéôôÞ ðïëõðëïêüôçôá ôïõ CGI. Ôï heitml Ý÷åé áíáðôõ÷èåß
óýìöùíá ìå ðñüóöáôåò Ýñåõíåò êáé óå óõóôÞìáôá êáôáóêåõÞò
ìåôáãëùôôéóôþí êáé äïóïëçøéþí (transaction).
Ïé óåëßäåò heitml áíáðôýóóïíôáé üðùò êáé ïé óåëßäåò HTML, ìå Ýíáí text
editor Þ Ýíáí HTML editor, êáé ôïðïèåôïýíôáé óôï web server ìå ôï
ãíùóôü ôñüðï. ÐáñüëáõôÜ, ïé óåëßäåò ìðïñïýí íá ðåñéÝ÷ïõí ôþñá äõíáìéêÜ
heitml tags êáé âéâëéïèÞêåò tag ãéá ðñüóâáóç óå âÜóåéò. Ìðïñåßôå íá
÷ñçóéìïðïéÞóåôå áõôÜ ôá tags ãéá íá Ý÷åôå ðñüóâáóç óå âÜóåéò, íá
äçìéïõñãÞóåôå äõíáìéêü ðåñéå÷üìåíï, íá óôåßëåôå emails, êáé íá
äçìéïõñãÞóåôå áêüìç éó÷õñÝò åöáñìïãÝò üðùò åããñáöÞ óå âÜóåéò êáé
óõóôÞìáôá áãïñþí.
Ïé íåüöåñôïé óôçí ãëþóóá HTML êáé ïé åðáããåëìáôßåò ðñïãñáììáôéóôÝò èá
ìåßíïõí Ýêðëçêôïé ìå ôï ðüóï ãñÞãïñá êáé åýêïëá ìðïñïýí íá ó÷åäéÜóïõí
åíäéáöÝñïõóåò åöáñìïãÝò üðùò ôï Interactive Guestbook ÷ùñßò íá
÷ñåéÜæåôáé íá ìÜèïõí íá ãñÜöïõí óýíèåôá êáé ðïëýðëïêá CGI scripts,
áðëÜ êáé ìüíï ÷ñçóéìïðïéþíôáò ôá åñãáëåßá ðïõ ðáñÝ÷ïíôáé ìå ôç dba
âéâëéïèÞêç ìáò.
Ôï heitml óõíïäåýåôáé áðü Ýíá ìåãÜëï ðëÞèïò tag âéâëéïèçêþí, ãéá íá
äçìéïõñãÞóåôå guestbooks, åöáñìïãÝò óõíôÞñçóçò ôçò âÜóçò, åðåêôÜóéìåò
öüñìåò åñùôÞóåùí, éó÷õñÝò öüñìåò email Þ íá äïìÞóôå ôï web site óáò
÷ñçóéìïðïéþíôáò Ýíá éåñáñ÷éêü ìåíïý. ÁõôÜ ôá åñãáëåßá åßíáé Ýôïéìá,
áðëÜ ðñïóèÝóôå ôá áíôßóôïé÷á tags óôï web site óáò.
Óáí Ýìðåéñïò ðñïãñáììáôéóôÞò, ìðïñåßôå íá êÜíåôå ðëÞñç ÷ñÞóç ôçò
heitml áñ÷éôåêôïíéêÞò äõíáìéêþí åããñáöþí: Ôï heitml äåí åßíáé áðëÜ ìéá
scripting ãëþóóá ìå äõíáìéêïýò ôýðïõò, éó÷õñÞ óôïí õðïëïãéóìü
åêöñÜóåùí, áíáäñïìéêÝò ñïõôßíåò êáé ðÝñáóìá åêôåôáìÝíùí ðáñáìÝôñùí,
áëëÜ ÷áñáêôçñßæåôáé åðßóçò áðü äõíáìéêÝò åããñáöÝò ãéá ôçí áõôüìáôç
äéá÷åßñéóç ôùí äåäïìÝíùí åíüò session áíåîáñôÞôïõ ìåãÝèïõò.
[1m14.5. America On-line AOL Web server ãéá PostgreSQL[0m
Ï äùñåÜí åìðïñéêüò webserver, AOLserver Ýêäïóçò 2.3 õðïóôçñßæåé
óõíäÝóåéò óôç âÜóç PostgreSQL Ýêäïóç 6.2.1 êáé ìåãáëýôåñç. Ãéá
ðåñéóóüôåñåò ðëçñïöïñßåò åðéóêåöôåßôå ôï
· AOL Web Server <http://www.aolserver.com>
[1m14.6. Problem/Project Tracking System Application Tool ãéá PostgreSQL[0m
Âñßóêåôáé óôï :
· <http://www.homeport.org/~shevett/pts/>
[1m14.7. ÌåôáôñïðÞ áñ÷åßùí dbase dbf óå PostgreSQL[0m
Ôï ðñüãñáììá dbf2msql äïõëåýåé Üøïãá ìå mSQL êáé PostgreSQL. Ìðïñåßôå
íá ôï âñåßôå óôï
· <ftp://ftp.nerosworld.com/pub/SQL/dbf2sql/>
· <ftp://ftp.postgresql.org/pub/incoming/dbf2pg-3.0.tar.gz>
Ôï ðñüãñáììá áõôü ãñÜöôçêå áðü ôïí Maarten Boekhold, Faculty of
Electrical Engineering TU Delft, NL Computer Architecture and Digital
Technique section
· M.Boekhold@et.tudelft.nl
Ìðïñåßôå íá ÷ñçóéìïðïéÞóåôå åðßóçò python ãéá íá äéáâÜóåôå áñ÷åßá dbf
êáé íá ôá öïñôþóåôå óå ìéá âÜóç äåäïìÝíùí postgres.
· Äåßôå ôï <http://www.python.org>
[1m15. Åñãáëåßï ãéá Ó÷åäéáóìü/Õëïðïßçóç Web ÂÜóåùí ÄåäïìÝíùí ãéá ôçí[0m
[1mPostgreSQL - EARP[0m
· <http://www.oswego.edu/Earp>
· <ftp://ftp.oswego.edu> óôïí êáôÜëïãï 'pub/unix/earp'.
[1m15.1. Ôé åßíáé ôï EARP ;[0m
Ôï EARP åßíáé Ýíá åñãáëåßï ãéá ó÷åäéáóìü/õëïðïßçóç Web âÜóåùí, ðïõ
êÜèåôáé ðÜíù áðü ôï óýóôçìá âÜóçò äåäïìÝíùí PostgreSQL. Óôç
ëåéôïõñãéêüôçôÜ ôïõ ðåñéëáìâÜíïíôáé:
· ¸íá óýóôçìá ãñáöéêïý ó÷åäéáóìïý.
· ¸íá interface ãéá sendmail. (ìðïñåß íá ÷åéñéóôåß ôá åéóåñ÷üìåíá êáé
åîåñ÷üìåíá mail)
· ¸íá áõîçìÝíï ìç÷áíéóìü áóöáëåßáò.
· ¸íáí ïäçãü cgi.
[1m15.2. Õëïðïßçóç[0m
Ç êýñéá õëïðïßçóç ôïõ EARP åßíáé Ýíá åêôåëÝóéìï CGI ðïõ ôñÝ÷åé êÜôù
áðü ôï äáßìïíá http êáé ðáñÝ÷åé ðñüóâáóç óôï äéáêïìéóôÞ ôçò âÜóçò
äåäïìÝíùí. ¼ëá ôá åñãáëåßá ó÷åäéáóìïý åßíáé ÷ôéóìÝíá ìÝóá óôïí ïäçãü,
ï ó÷åäéáóìüò äåí ãßíåôáé ðáñÜ ìüíï óå web. Ôá ßäéá ôá åñãáëåßá
áðáéôïýí Ýíá ãñáöéêü browser, ç óõìâáôüôçôá ôùí áíôéêåéìÝíùí ðïõ
ó÷åäéÜæïíôáé ìå ôá åñãáëåßá åßíáé áíåîÜñôçôá ôïõ ôñüðïõ õëïðïßçóçò,
âáóéóìÝíá óôï ó÷åäéáóìü áôïìéêþí ðñïôéìÞóåùí.
[1m15.3. Ôé ÷ñåéÜæåóôå ãéá íá ôñÝîåôå ôï EARP[0m
Ôï EARP ðñÝðåé íá ôñÝ÷åé ðéèáíÜ óå ðïëëÝò ðëáôöüñìåò ìå ëßãï Þ êáèüëïõ
ìåôáöïñÜ. Ïé ãíùóôÝò ðëáôöüñìåò ðïõ ôñÝ÷åé åßíáé ïé åîÞò:
· Solaris 2.5
· Linux 1.2.13+
· GNU C++
· PostgreSQL (Ýêäïóç 1.01 / 1.02 )
· netsite server
· NCSA httpd
· GNU C++
· PostgreSQL (Ýêäïóç 1.01 / 1.02 )
· NCSA httpd
· Apache httpd
Ç ôñÝ÷ïõóá Ýêäïóç (1.3) ôïõ Earp ó÷åäéÜóôçêå ðÜíù óôçí Ýêäïóç ôïõ
libpq ðïõ Ýñ÷åôáé ìå ôçí PostgreSQL v1.01/1.02. Áí ÷ñçóéìïðïéåßôå
ìéá ðéï ðñüóöáôç Ýêäïóç ôçò Postgres, íá ðåñéìÝíåôå ðùò ôï
ðñüãñáììá èá ÷ñåéáóôåß ìåñéêÝò áëëáãÝò ãéá íá äïõëÝøåé óùóôÜ. Óôçí
áíáðôõóóüìåíç Ýêäïóç (Earp 2.0), ç õðïóôÞñéîç libpq åíóùìáôþíåôáé
óáí module.
[1m15.4. Ðþò äïõëåýåé ;[0m
¸íá áðü ôá êõñéüôåñá ÷áñáêôçñéóôéêÜ ôïõ EARP åßíáé üôé ÷ñçóéìïðïéåß
ÁíôéêåéìåíïóôñáöÞ ìÝèïäï ãéá íá ðáñÜãåé html óåëßäåò ðïõ åðéêïéíùíïýí
ìå ôç âÜóç. Ïé ðåñéóóüôåñåò óåëßäåò áðïôåëïýíôáé áðü äéÜöïñá
áíôéêåßìåíá (objects). ÊÜèå áíôéêåßìåíï ðáñÜãåôáé áðü êÜðïéïõ ôýðïõ
åñãáëåßï êáé áöïý ôïõ äïèåß Ýíá üíïìá, ôá áíôéêåßìåíá óõíäÝïíôáé
ìåôáîý ôïõò óå ìßá áëëçëïõ÷ßá ðïõ ìðïñåß íá êáëåóôåß áðü ôï åñãáëåßï
ôçò óåëßäáò (page tool). Ôá áíôéêåßìåíá åßíáé ìðïñïýí íá
÷ñçóéìïðïéçèïýí áðü ðïëëáðëÝò óåëßäåò. ÕðÜñ÷ïõí âáóéêÜ åñãáëåßá ãéá
HTML, ÅñùôÞóåéò (Querys), íá ðáßñíåôå ôéìÝò áðü ôéò öüñìåò, íá
öïñìÜñåôå åñùôÞóåéò êáé áíôéêåßìåíá åéóüäïõ, êáé íá óõíäÝåôå ìåôáîý
ôïõò ôá áíôéêåßìåíá óå Üëëá áíôéêåßìåíá. Ðåñéóóüôåñá åîåëéãìÝíá
åñãáëåßá ðåñéëáìâÜíïõí ôï åñãáëåßï ãéá mail êáé ôï multithreaded
åñãáëåßï åñùôÞóåùí.
Áëëï ÷áñáêôçñéóôéêü ôïõ EARP åßíáé ç Ýîôñá áóöÜëåéá. Ç ðñüóâáóç óå
äéÜöïñåò ðåñéï÷Ýò ôïõ óõóôÞìáôïò EARP ìðïñåß íá ðåñéïñéóôåß ìå
äéÜöïñïõò ôñüðïõò. Ãéá íá åõêïëýíåé ôçí Ýîôñá áóöÜëåéá, ôï EARP
åëÝã÷åé ãéá êÜèå óýíäåóç óôï óýóôçìá, êáé ðñïóäéïñßæåé óå ðïéá ids êáé
ãêñïõð áíÞêåé ï óõíäåäåìÝíïò agent. Ç ðñüóâáóç óå ðåñéï÷Ýò êáèïñßæåôáé
îå÷ùñéóôÜ, êáé ï óõíäõáóìüò áðïöáóßæåé áí åðéôñÝðåôáé ç ðñüóâáóç óå
ìéá óõãêåêñéìÝíç ðåñéï÷Þ ôïõ Earp. ÅðéðëÝïí, ü,ôé áðáéôåßôáé ãéá íá
õëïðïéÞóåôå ôá ÷áñáêôçñéóôéêÜ áóöáëåßáò åßíáé Ýíáò http server ðïõ
õðïóôçñßæåé âáóéêü (Þ êáëýôåñá) user authentication.
[1m15.5. Ðïý èá ôï âñù ;[0m
Ìðïñåßôå íá êáôåâÜóåôå ôï EARP ìå anonymous ftp áðü ôï
· <ftp://ftp.oswego.edu> óôïí êáôÜëïãï 'pub/unix/earp'.
[1m16. PHP Hypertext Preprocessor, ìéá scripting ãëþóóá ãéá ôçí Post-[0m
[1mgreSQL ç ïðïßá åíóùìáôþíåôáé óå html êáé åêôåëåßôáé óôï Server[0m
Åñãáëåßï äéáóýíäåóçò ìå ôï WWW
· <http://www.php.net>
· <http://www.vex.net/php>
Ôï ðáëéü üíïìá åßíáé Professional Home Pages (PHP 3) êáé ôï íÝï
üíïìá åßíáé PHP Hypertext Pre-Processor
· ÕðÜñ÷ïõí Mirror sites óå ðïëëÝò ÷þñåò üðùò ôï
www.COUNTRYCODE.php.net
· <http://www.fe.de.php.net>
· <http://www.sk.php.net>
· <http://php.iquest.net/>
Ãéá åñùôÞóåéò, óôåßëôå e-mail óôï :
· rasmus@lerdorf.on.ca
Ôï PHP 3 åßíáé ìéá scripting ãëþóóá ãéá ôçí PostgreSQL ç ïðïßá
åíóùìáôþíåôáé óå html êáé åêôåëåßôáé óôï Server. Óáò åðéôñÝðåé íá
ãñÜöåôå áðëÜ scripts óôá áñ÷åßá .HTML ðáñüìïéá ìå ôçí JavaScript, ìüíï
ðïõ áíôßèåôá ìå ôçí JavaScript, ôï PHP 3 äåí åîáñôÜôáé áðü ôï browser.
Ôï JavaScript åßíáé ìéá ãëþóóá ç ïðïßá åíóùìáôþíåôáé óå html êáé
ôñÝ÷åé óôï client-ìÝñïò åíþ ôï PHP 3 åêôåëåßôáé óôï Server. Ôï PHP 3
åßíáé ðáñüìïéï óôçí óýëëçøç ìå ôï ðñïúüí ôçò Netscape LiveWire Pro. Áí
Ý÷åôå ôá áðáéôïýìåíá ÷ñÞìáôá, êáé ôñÝ÷åôå ôïí åìðïñéêü Server ôçò
Netscape êáé Ý÷åôå Ýíá áðü ôá õðïóôçñéæüìåíá ëåéôïõñãéêÜ óõóôÞìáôá,
ßóùò èá ðñÝðåé íá ñßîåôå ìéá ìáôéÜ óôï LiveWire Pro. Áí óáò áñÝóåé ôï
äùñåÜí, ôá÷ýôáôá áíáðôõóóüìåíï ëïãéóìéêü ðïõ Ýñ÷åôáé ìå üëï ôïí ðçãáßï
êþäéêá ðéèáíÜ íá óáò áñÝóåé ôï PHP 3.
[1m16.1. Êýñéá ÷áñáêôçñéóôéêÜ[0m
ÕðïóôÞñéîç óôÜíôáñ CGI, FastCGI êáé Apache module. Óáí Ýíá óôÜíôáñ
ðñüãñáììá CGI, ôï PHP 3 ìðïñåß íá åãêáôáóôáèåß óå ïðïéáäÞðïôå ìç÷áíÞ
Unix êáé íá ôñÝîåé óå ïðïéïäÞðïôå Unix web server. Ìå ôçí õðïóôÞñéîç
ôïõ íÝïõ óôÜíôáñ FastCGI, ôï PHP 3 Ý÷åé ôï ðëåïíÝêôçìá ôùí âåëôéþóåùí
óôçí ôá÷ýôçôá ðïõ ïöåßëïíôáé óå áõôü ôï ìç÷áíéóìü. Óáí Apache module,
ôï PHP 3 ãßíåôáé åîáéñåôéêÜ éó÷õñü êáé ôñïìáêôéêÜ ãñÞãïñç åíáëëáêôéêÞ
ôïõ ðñïãñáììáôéóìïý óå CGI.
· ÊáôáãñáöÞ ôùí ðñïóâÜóåùí (Access Logging) Ìå ôç äõíáôüôçôá
êáôáãñáöÞò ôùí ðñïóâÜóåùí ôïõ PHP 3, ïé ÷ñÞóôåò ìðïñïýí íá
óõíôçñÞóïõí ôï äéêü ôïõò ìåôñçôÞ êáé êáôáãñáöÝá ðñïóâÜóåùí (hit
counting and logging). Äå ÷ñçóéìïðïéåß ìå êáíÝíá ôñüðï ôá êåíôñéêÜ
áñ÷åßá ðñüóâáóçò óôï óýóôçìá, êáé ðáñÝ÷åé ðáñáêïëïýèçóç ðñïóâÜóåùí
óå ðñáãìáôéêü ÷ñüíï. Ôï Log Viewer Script ðáñÝ÷åé ìéá óýíôïìç
ðåñßëçøç ôùí ðñïóâÜóåùí óå Ýíá óýíïëï óåëßäùí ãéá êÜèå îå÷ùñéóôü
÷ñÞóôç. ÅðéðëÝïí, ôï ðáêÝôï ìðïñåß íá ñõèìéóôåß þóôå íá ðáñÜãåé Ýíá
footer óå êÜèå óåëßäá ôï ïðïßï äåß÷íåé ðëçñïöïñßåò ó÷åôéêÜ ìå ôçí
ðñüóâáóç. Äåßôå ôï ôÝëïò áõôÞò ôçò óåëßäáò ãéá Ýíá ðáñÜäåéãìá óå
áõôÜ.
· ¸ëåã÷ïò ðñïóâÜóåùí Ìéá åíóùìáôùìÝíç ïèüíç, âáóéóìÝíç óôï web,
÷åéñßæåôáé ôéò ñõèìßóåéò ãéá ôïí Ýëåã÷ï ôùí ðñïóâÜóåùí. Åßíáé
äõíáôü íá äçìéïõñãÞóåôå êáíüíåò ãéá üëåò Þ êÜðïéåò áðü ôéò web
óåëßäåò ðïõ Ý÷åé êÜðïéï óõãêåêñéìÝíï Üôïìï, ôï ïðïßï èÝôåé
äéÜöïñïõò ðåñéïñéóìïýò ãéá ôï ðïéïò ìðïñåß íá âëÝðåé áõôÝò ôéò
óåëßäåò êáé ðþò èá ôéò âëÝðåé. Ïé óåëßäåò ìðïñåß íá ðñïóôáôåýïíôáé
ìå êùäéêü, íá åßíáé ðëÞñùò áðáãïñåõìÝíåò, íá åßíáé áðåíåñãïðïéçìÝíç
ç êáôáãñáöÞ (logging disabled) êáé áêüìç ðåñéóóüôåñá âáóéóìÝíá óôï
domain ôïõ client, browser,ôç äéåýèõíóç e-mail Þ áêüìç êáé ôï
ó÷åôéêü êåßìåíï.
· ÕðïóôÞñéîç ãéá Postgres Ç Postgres åßíáé Ýíá åîåëéãìÝíï äùñåÜí
RDBMS. Ôï PHP 3 õðïóôçñßæåé ôçí åíóùìÜôùóç Postgres95 êáé
PostgresSQL SQL åñùôÞóåùí êáôåõèåßáí ìÝóá óå áñ÷åßá .html.
· ÕðïóôÞñéîç RFC-1867 ÁðïóôïëÞ/ÁíÝâáóìá Áñ÷åßùí (File Upload) Ôï
Upload áñ÷åßùí åßíáé Ýíá íÝï ÷áñáêôçñéóôéêü óôï Netscape 2.0.
ÅðéôñÝðåé óôïõò ÷ñÞóôåò íá óôåßëïõí (upload) ôá áñ÷åßá ôïõò óôï web
server. Ôï PHP 3 ðáñÝ÷åé ôï ðñáãìáôéêü Mime decoding ãéá íá ôï
êÜíåé áõôü íá äïõëÝøåé êáé åðßóçò ðáñÝ÷åé ôï ðëáßóéï ãéá íá êÜíåôå
êÜôé ÷ñÞóéìï ìå ôï áñ÷åßï ðïõ óôåßëáôå, ìüëïò ôï ëÜâåé ï server.
· HTTP-based authentication control Ôï PHP 3 ìðïñåß íá ÷ñçóéìïðïéçèåß
ãéá íá äçìéïõñãÞóåé ìç÷áíéóìïýò authentication åðß ðáñáããåëßá,
âáóéóìÝíïõò óå HTTP, ãéá ôïí Apache web server.
· ÌåôáâëçôÝò, Ðßíáêåò (arrays), Óõó÷åôéóôéêïß ðßíáêåò (Associative
Arrays) Ôï PHP 3 õðïóôçñßæåé ìåôáâëçôÝò ôýðùí (typed variables),
ðßíáêåò êáé áêüìç êáé Perl-ïåéäåßò óõó÷åôéóôéêïýò ðßíáêåò
(associative arrays). ¼ëá áõôÜ ìðïñïýí íá ðåñíïýí áðü ôç ìßá web
óåëßäá óôçí Üëëç ÷ñçóéìïðïéþíôáò ôéò ìåèüäïõò ôùí öïñìþí, GET Þ
POST.
· Conditionals, While Loops Ôï PHP 3 õðïóôçñßæåé ìéá ãëþóóá scripting
ìå üëá ôá ÷áñáêôçñéóôéêÜ ôçò C. Ìðïñåßôå íá Ý÷åôå óõíèÞêåò
if/then/elseif/else/endif üðùò êáé while loops êáé äçëþóåéò
switch/case ãéá íá ðåñéãñÜøåé ôç ëïãéêÞ ñïÞ ôïõ ðþò èá åìöáíßæåôáé
ç html óåëßäá.
· Extended Regular Expressions Ôá Regular expressions
÷ñçóéìïðïéïýíôáé ðïëý ãéá ôáõôïðïßçóç (pattern matching),
áíôéêáôáóôÞóåéò ôùí pattern êáé ãåíéêü ÷åéñéóìü áëöáñéèìçôéêþí. Ôï
PHP 3 õðïóôçñßæåé üëïõò ôïõò êïéíïýò ôåëåóôÝò êáíïíéêþí åêöñÜóåùí.
· Raw HTTP Header Control Ç äõíáôüôçôá íá êÜíïõìå ôéò web óåëßäåò íá
óôÝëíïõí åéäéêÜ ôñïðïðïéçìÝíåò åðéêåöáëßäåò HTTP áíÜëïãá ìå êÜðïéåò
óõíèÞêåò åßíáé áðáñáßôçôï ãéá ó÷åäéáóìü web sites õøçëïý åðéðÝäïõ.
Óõ÷íÞ ÷ñÞóç áõôïý, åßíáé ç áðïóôïëÞ ìéáò ôïðïèåóßáò: URL header ãéá
áíáêáôåýèõíóç ôïõ ðåëÜôç ðïõ Ýêáíå ôçí êëÞóç ðñïò Üëëï URL. Ìðïñåß
íá ÷ñçóéìïðïéçèåß åðßóçò ãéá íá áðåíåñãïðïéÞóïõìå ôï caching Þ íá
åðåîåñãáóôïýìå ôçí ôåëåõôáßá åðéêåöáëßäá åíçìÝñùóçò.
· Äçìéïõñãßá GIF åéêüíáò åðß ôüðïõ/óôïí áÝñá (On-the-fly) Ôï PHP 3
õðïóôçñßæåé ôç GD âéâëéïèÞêç åéêüíùí ôïõ Thomas Boutell ç ïðïßá óáò
äßíåé ôç äõíáôüôçôá íá äçìéïõñãÞóåôå GIF åéêüíåò åðß ôüðïõ.
· ÕðïóôÞñéîç ISP "Safe Mode" Ôï PHP 3 õðïóôçñßæåé ôï ìïíáäéêü "Safe
Mode" ôï ïðïßï êÜíåé áóöáëÝò ôï íá Ý÷åôå ðïëëïýò ÷ñÞóôåò íá ôñÝ÷ïõí
PHP scripts óôïí ßäéï server.
· Åßíáé äùñåÜí! Êáé ôï ôåëéêü ïõóéáóôéêü ÷áñáêôçñéóôéêü. Ôï ðáêÝôï
åßíáé åíôåëþò äùñåÜí. Âñßóêåôáé êÜôù áðü ôçí Üäåéá GPL ç ïðïßá óáò
åðéôñÝðåé íá ÷ñçóéìïðïéÞóåôå ôï ëïãéóìéêü ãéá ïðïéïäÞðïôå óêïðü,
åìðïñéêü Þ ïðïéïíäÞðïôå Üëëï. Äåßôå ôï êåßìåíï ôçò äçìüóéáò Üäåéáò
GNU ãéá ðåñéóóüôåñåò ëåðôïìÝñåéåò.
[1m16.2. Áíáãíþñéóç/Åõ÷áñéóôßåò[0m
* ÌåãÜëá êïììÜôéá áõôïý ôïõ êþäéêá áíáðôý÷èçêáí óôï êáé ãéá ôï
ÐáíåðéóôÞìéï ôïõ Ôïñüíôï. ÐïëëÝò åõ÷áñéóôßåò óôïí Lee Oattes ôïõ
ÔìÞìáôïò ÁíÜðôõîçò Äéêôýùí ôïõ ðáíåðéóôçìßïõ ãéá ôéò óõíå÷åßò
åðïéêïäïìçôéêÝò êñéôéêÝò ôïõ.
* Ï êþäéêáò õðïóôÞñéîçò ôçò PostgreSQL ãñÜöôçêå áðü ôïí Adam Sussman
· asussman@vidya.com
* Áíáñßèìçôïé Üëëïé, âïÞèçóáí óôï íá åëåã÷èåß êáé íá áðïóöáëìáôùèåß ôï
ðáêÝôï.
[1m16.3. PHP 3 - Óýíôïìï Éóôïñéêü[0m
Ôï PHP îåêßíçóå ôçí æùÞ ôïõ ùò cgi êþäéêáò åðéêÜëõøçò (cgi wrapper)
ãñáììÝíïò óå Perl. Äåí ðñïïñéæüôáí ãéá ôßðïôá ðÝñá áðü ðñïóùðéêÞ
÷ñÞóç. Ôï üíïìá ôïõ ðñþôïõ áõôïý ðáêÝôïõ Þôáí Personal Home Page
Tools, êáé áñãüôåñá Ýãéíå Personal Home Page Construction Kit.
ÃñÜöôçêå Ýíá åñãáëåßï ãéá íá åíóùìáôþíåé åýêïëá åñùôÞóåéò SQL óå web
óåëßäåò. ¹ôáí âáóéêÜ Ýíá áêüìá CGI wrapper ðïõ ìåôÝöñáæå åñùôÞóåéò SQL
êáé Ýêáíå ôçí äçìéïõñãßá öïñìþí êáé ðéíÜêùí áðü ôéò åñùôÞóåéò ìéá
åýêïëç õðüèåóç. Ôï åñãáëåßï áõôü ïíïìÜóôçêå FI (Form Interpreter).
Ôï PHP/FI Ýêäïóç 2.0 åßíáé Ýíá åíéáßï ðñüãñáììá, åî'ïëïêëÞñïõ
îáíáãñáììÝíï, ðïõ áðïôåëåß ôïí óõíäõáóìü ôùí äýï ðáñáðÜíù ðáêÝôùí.
¸÷åé ôþñá ðéá åîåëé÷èåß óå óçìåßï ðïõ åßíáé ìéá áðëÞ ðñïãñáììáôéóôéêÞ
ãëþóóá åíóùìáôùìÝíç óå áñ÷åßá HTML. Ôï áñ÷éêü áêñùíýìéï, PHP, Ýìåéíå.
Äåí åßíáé êáí áíôéðñïóùðåõôéêü ðéá. Ôï PHP/FI ÷ñçóéìïðïéåßôáé
ðåñéóóüôåñï áðü ïëüêëçñá web sites óÞìåñá, ðáñÜ ãéá ìéêñÝò
åãêáôáóôÜóåéò Ðñïóùðéêþí Óåëßäùí (Personal Home Page). Ìå üðïéï üíïìá,
åîáëåßöåé ôçí áíÜãêç ãéá ôá ðïëõÜñéèìá ìéêñÜ Perl cgi ðñïãñÜììáôá,
åðéôñÝðïíôáò óáò íá âÜëåôå ìéêñÜ scripts áðåõèåßáò óôá HTML áñ÷åßá
óáò. Áõôü åðéôá÷ýíåé ôçí ïëéêÞ ôá÷ýôçôá ôùí web pages óáò, ìéá ðïõ ç
êáèõóôÝñçóç ôïõ êëùíéóìïý (forking) ôçò Perl óå ðïëëáðëÜ áíôßôõðá Ý÷åé
åîáëåéöèåß. ÊÜíåé åðßóçò åõêïëüôåñç ôçí äéá÷åßñéóç ìåãÜëùí web sites
ôïðïèåôþíôáò üëá ôá óõóôáôéêÜ ìéáò web page óå Ýíá ìüíï html áñ÷åßï.
Åíóùìáôþíïíôáò õðïóôÞñéîç ãéá äéÜöïñåò âÜóåéò, êÜíåé ôçí áíÜðôõîç
óåëßäùí-ìå-äõíáôüôçôåò-÷ñÞóçò-âÜóçò ôåôñéììÝíç. Ðïëëïß âñßóêïõí ôçí
åíóùìáôùìÝíç öýóç ôïõ ðñïãñÜììáôïò ðïëý åõêïëüôåñç ðáñÜ ôï íá
ðñïóðáèïýí íá äçìéïõñãïýí îå÷ùñéóôÜ áñ÷åßá HTML êáé CGI.
ÊáôÜ ôç äéÜñêåéá áõôÞò ôçò ôåêìçñßùóçò, êÜèå áíáöïñÜ óôï PHP, FI Þ óôï
PHP/FI ìéëÜåé ãéá ôï ßäéï ðñÜãìá. Ïé äéáöïñÜ ìåôáîý ôïõ PHP êáé ôïõ FI
åßíáé ìüíï èÝìá áíôßëçøçò. Êáé ôá äýï ÷ôßæïíôáé áðü ôïí êþäéêá ôçò
ßäéáò äéáíïìÞò. Ôþñá ôï PHP/FI ìåôïíïìÜóôçêå óå PHP 3.
[1m16.4. Ôé ìðïñþ íá êÜíù, ëïéðüí, ìå ôï PHP/FI ;[0m
Ôï ðñþôï ðñÜãìá ðïõ èá ðáñáôçñÞóåôå áí ôñÝîåôå ìéá óåëßäá ìÝóù ôïõ
PHP/FI åßíáé üôé ðñïóèÝôåé Ýíá footer ìå ðëçñïöïñßåò ó÷åôéêÜ ìå ôïí
áñéèìü ðñïóâÜóåùí óôç óåëßäá óáò (áí Ý÷åôå ìåôáãëùôôßóåé ôçí êáôáãñáöÞ
ðñïóâÜóåùí óôï åêôåëÝóéìï). Áõôü åßíáé Ýíá ðïëý ìéêñü äåßãìá ôïõ ôé
ìðïñåß íá êÜíåé ãéá óáò ôï PHP/FI. Ðáßæåé ôïí åîßóïõ óçìáíôéêü ñüëï
ôïõ ìåôáöñáóôÞ cgi óå öüñìåò, áðü åêåß âãáßíåé êáé to FI ìÝñïò ôïõ
ïíüìáôïò. Ãéá ðáñÜäåéãìá, áí äçìéïõñãÞóåôå ìéá öüñìá óå ìßá áðü ôéò
web óåëßäåò óáò, ÷ñåéÜæåóôå êÜôé ãéá íá åðåîåñãáóôåß ôçí ðëçñïöïñßá óå
áõôÞ ôç öüñìá. Áêüìç êáé áí áðëÜ èÝëåôå íá ðåñÜóåôå ðëçñïöïñßá óå ìéá
Üëëç óåëßäá, èá ðñÝðåé íá ÷ñçóéìïðïéÞóåôå Ýíá ðñüãñáììá cgi ãéá íá ôï
êÜíåôå áõôü. To PHP/FI êÜíåé åîáéñåôéêÜ åýêïëï ôï íá ðÜñåôå äåäïìÝíá
áðü ìéá öüñìá êáé íá êÜíåôå êÜôé ìå áõôÜ.
[1m16.5. ¸íá áðëü ðáñÜäåéãìá[0m
Áò õðïèÝóïõìå üôé Ý÷åôå ìéá öüñìá:
<FORM ACTION="/cgi-bin/php.cgi/~userid/display.html" METHOD=POST>
<INPUT TYPE="text" name="name">
<INPUT TYPE="text" name="age">
<INPUT TYPE="submit">
<FORM>
Ôï áñ÷åßï display.html èá ìðïñïýóå íá ðåñéÝ÷åé êÜôé óáí ôï ðáñáêÜôù:
< ?echo "Hi $ name, you are $ age years old!<p>" >
Åßíáé ôüóï áðëü! Ôï PHP/FI äçìéïõñãåß áõôüìáôá ìéá ìåôáâëçôÞ ãéá êÜèå
input field óôç öüñìá óáò. Ìðïñåßôå ôüôå íá ÷ñçóéìïðïéÞóåôå áõôÝò ôéò
ìåôáâëçôÝò óôï áñ÷åßï ACTION URL.
Ôï åðüìåíï âÞìá áöïý Ý÷åôå êáôáëÜâåé ðþò íá ÷ñçóéìïðïéåßôå ôéò
ìåôáâëçôÝò åßíáé íá îåêéíÞóåôå íá ðáßæåôå ìå ìåñéêÜ tags ëïãéêÞò ñïÞò
óôéò óåëßäåò óáò. Ãéá ðáñÜäåéãìá, áí èÝëáôå íá åìöáíßóåôå äéáöïñåôéêÜ
ìçíýìáôá âáóéóìÝíá óå êÜôé ðïõ åéóÜãåé ï ÷ñÞóôçò, èá ÷ñçóéìïðïéïýóáôå
ôç ëïãéêÞ if/else. Óôï ðáñáðÜíù ðáñÜäåéãìá, ìðïñïýìå íá åìöáíßóïõìå
äéáöïñåôéêÜ ðñÜãìáôá ìå âÜóç ôçí çëéêßá ðïõ Ýäùóå ï ÷ñÞóôçò áëëÜæïíôáò
ôï áñ÷åßï display.html ùò åîÞò:
<?
if($age>50);
echo "Hi $name, you are ancient!<p>";
elseif($age>30);
echo "Hi $name, you are very old!<p>";
else;
echo "Hi $name.";
endif;
>
Ôï PHP/FI ðáñÝ÷åé ìßá ðïëý éó÷õñÞ scripting ãëþóóá ðïõ èá êÜíåé ðïëý
ðåñéóóüôåñá áð' üôé êÜíïõí ôá ðáñáðÜíù áðëÜ ðáñáäåßãìáôá. Äåßôå ôï
ôìÞìá óôï "PHP/FI Script Language" ãéá ðåñéóóüôåñåò ðëçñïöïñßåò.
Ìðïñåßôå íá êáèïñßóåôå åðßóçò óôï PHP/FI ðïéïò åðéôñÝðåôáé íá Ý÷åé
ðñüóâáóç óôéò óåëßäåò óáò. Áõôü åðéôõã÷Üíåôáé ìå ìéá åíóùìáôùìÝíç
ïèüíç ñýèìéóçò. Ìå áõôÞ èá ìðïñïýóáôå ãéá ðáñÜäåéãìá íá êáèïñßóåôå üôé
ìüíï ôá Üôïìá áðü óõãêåêñéìÝíá domains èá ìðïñïýí íá äïõí ôéò óåëßäåò
óáò, Þ èá ìðïñïýóáôå íá äçìéïõñãÞóåôå Ýíá êáíüíá ðïõ èá ðñïóôÜôåõå
ìåñéêÝò óåëßäåò óáò ìå êùäéêü. Äåßôå ôï ôìÞìá "¸ëåã÷ïò ðñïóâÜóåùí" ãéá
ðåñéóóüôåñåò ðëçñïöïñßåò.
Ôï PHP/FI åßíáé åðßóçò éêáíü íá äÝ÷åôáé uploads áñ÷åßùí áðü
ïðïéïäÞðïôå web browser óõìâáôü ìå RFC-1867. Áõôü ôï ÷áñáêôçñéóôéêü
åðéôñÝðåé óå áíèñþðïõò íá áíåâÜóïõí êáé text êáé binary áñ÷åßá. Ìå ôïí
Ýëåã÷ï ðñïóâÜóåùí ôïõ PHP/FI êáé ôéò ëïãéêÝò óõíáñôÞóåéò, Ý÷åôå ðëÞñç
Ýëåã÷ï ðÜíù óôï ðïéïò åðéôñÝðåôáé íá áíåâÜæåé (upload) áñ÷åßá êáé ôé
ìðïñåß íá êÜíåé ìå ôï áñ÷åßï áöïý ôï áíåâÜóåé. Äåßôå ôï ôìÞìá "File
Upload" ãéá ðåñéóóüôåñåò ðëçñïöïñßåò.
Ôï PHP/FI õðïóôçñßæåé ôï ðáêÝôï âÜóçò äåäïìÝíùí PostgreSQL.
Õðïóôçñßæåé åíóùìáôùìÝíåò SQL åñùôÞóåéò óôá .HTML áñ÷åßá óáò. Äåßôå ôï
áíôßóôïé÷ï ôìÞìá óôçí "ÕðïóôÞñéîç ôçò PostgreSQL" ãéá ðåñéóóüôåñåò
ðëçñïöïñßåò.
Ôï PHP/FI õðïóôçñßæåé åðßóçò êáé ôï ðáêÝôï âÜóçò äåäïìÝíùí mysql.
Õðïóôçñßæåé åíóùìáôùìÝíåò SQL åñùôÞóåéò óôá .HTML áñ÷åßá óáò. Äåßôå ôï
áíôßóôïé÷ï ôìÞìá óôçí "ÕðïóôÞñéîç ôçò mysql" ãéá ðåñéóóüôåñåò
ðëçñïöïñßåò.
[1m16.6. CGI Redirection[0m
[1m16.6.1. Óçìåéþóåéò ãéá ôïí Apache 1.0.x[0m
Åíáò êáëüò ôñüðïò íá ôñÝîåôå ôï PHP/FI åßíáé ÷ñçóéìïðïéþíôáò Ýíá cgi
redirection module ìå ôïí Apache server. Ðáñáêáëþ óçìåéþóôå üôé äå
÷ñåéÜæåôáé íá áíçóõ÷åßôå ãéá modules áíáêáôåýèõíóçò áí ÷ñçóéìïðïéåßôå
ôçí Ýêäïóç ôïõ Apache module ôïõ PHP/FI. ÕðÜñ÷ïõí äýï áðü áõôÜ ôá
modules áíáêáôåýèõíóçò äéáèÝóéìá. ¸íá áðü áõôÜ áíáðôý÷èçêå áðü ôïí
Dave Andersen
· angio@aros.net
êáé åßíáé äéáèÝóéìï óôï
· <ftp://ftp.aros.net/pub/util/apache/mod_cgi_redirect.c>
êáé ôï Üëëï Ýñ÷åôáé ðáêÝôï ìå ôïí Apache êáé ëÝãåôáé mod_actions.c.
ÁõôÜ ôá modules åßíáé åîáéñåôéêÜ ðáñüìïéá. ÄéáöÝñïõí åëáöñÜ óôç
÷ñÞóç ôïõò. Êáé ôá äýï Ý÷ïõí ôåóôáñéóôåß êáé äïõëåýïõí ìå
ôï PHP/FI.
Äåßôå ôçí ôåêìçñßùóç ôïõ Apache ãéá ôï ðþò ìðïñåßôå íá ðñïóèÝóåôå Ýíá
module. ÃåíéêÜ, ðñïóèÝôåôå ôï üíïìá ôïõ module óå Ýíá áñ÷åßï ðïõ
ïíïìÜæåôáé Configuration. Ç ãñáììÞ ðïõ ðñÝðåé íá ðñïóèÝóåôå áí èÝëåôå
íá ÷ñçóéìïðïéÞóåôå ôï module mod_actions åßíáé:
Module action_module mod_actions.o
Áí ÷ñçóéìïðïéåßôå ôï module mod_cgi_redirect.c ðñïóèÝóôå áõôÞ ôç
ãñáììÞ:
Module cgi_redirect_module mod_cgi_redirect.o
Óôç óõíÝ÷åéá, ìåôáãëùôôßóôå ôï httpd êáé åãêáôáóôÞóôå ôï. Ãéá íá
ñõèìßóåôå ôï cgi redirection ÷ñåéÜæåôáé åßôå íá äçìéïõñãÞóåôå Ýíá íÝï
ôýðï mime óôï áñ÷åßï óáò mime.types åßôå íá ÷ñçóéìïðïéÞóåôå ôçí åíôïëÞ
AddType óôï áñ÷åßï óáò srm.conf ãéá íá ðñïóèÝóåôå ôïí mime ôýðï. Ãéá
íá ðñïóèÝóåôå ôïí ôýðï mime èá ðñÝðåé íá Ý÷åôå êÜôé óáí ôï ðáñáêÜôù:
application/x-httpd-php phtml
Áí ÷ñçóéìïðïéåßôå ôï module mod_actions.c, ÷ñåéÜæåôáé íá ðñïóèÝóåôå
ôçí ðáñáêÜôù ãñáììÞ óôï áñ÷åßï óáò srm.conf :
Action application/x-httpd-php /cgi-bin/php.cgi
Áí ÷ñçóéìïðïéåßôå ôï mod_cgi_redirect.c èá ðñÝðåé íá ðñïóèÝóåôå ôçí
ðáñáêÜôù ãñáììÞ óôï áñ÷åßï srm.conf :
CgiRedirect application/x-httpd-php /cgi-bin/php.cgi
Ìçí ÷ñçóéìïðïéÞóåôå ôáõôü÷ñïíá êáé ôá äýï mod_actions.c êáé
mod_cgi_redirect.c.
Áöïý Ý÷åôå åãêáôáóôÞóåé Ýíá áðü ôá cgi redirection modules êáé ôá
ñõèìßóåôå óùóôÜ, èá ìðïñåßôå íá ðñïóäéïñßóåôå üôé èÝëåôå Ýíá áñ÷åßï íá
ãßíåé parsed áðü ôï php/fi áðëÜ áëëÜæïíôáò ôï extension ôïõ áñ÷åßïõ óå
.phtml. ÅðéðëÝïí, áí ðñïóèÝóåôå Ýíá index.phtml óôç ãñáììÞ
DirectoryIndex ôïõ áñ÷åßïõ óáò srm.conf, ôüôå ç top-level óåëßäá óôïí
êáôÜëïãï èá ãßíåé áõôüìáôá parsed áðü ôï php áí ôï index áñ÷åßï
ïíïìÜæåôáé index.phtml.
[1m16.6.2. Netscape HTTPD[0m
Ìðïñåßôå íá áíáêáôåõèýíåôå áõôüìáôá ôéò áéôÞóåéò ãéá áñ÷åßá ìå
óõãêåêñéìÝíç êáôÜëçîç áñ÷åßïõ þóôå íá ôá ÷åéñéóôåß ôï PHP/FI ìå ôç
÷ñÞóç ôïõ Netscape Server CGI Redirection module. Áõôü ôï module åßíáé
äéáèÝóéìï óôï "File Archives" óôç óåëßäá ôïõ PHP/FI. Ôï áñ÷åßï README
ðïõ õðÜñ÷åé ìÝóá óôï ðáêÝôï åîçãåß êáèáñÜ ðþò íá ôï ñõèìßóåôå ãéá
÷ñÞóç ìå ôï PHP/FI.
[1m16.6.3. NCSA HTTPD[0m
Ï NCSA äåí õðïóôçñßæåé ðñïò ôï ðáñþí modules, êáé Ýôóé ãéá íá êÜíïõìå
áíáêáôåýèõíóç cgi ìå ôïí server áõôüí, èá ÷ñåéáóôåßôå íá ôñïðïðïéÞóåôå
ôïí êþäéêá ôïõ server óáò. Ìéá äéüñèùóç/ìðÜëùìá (patch) ðïõ ôï êÜíåé
ãéá ôïí NCSA 1.5 äéáôßèåôáé óôá áñ÷åßá ôïõ site ôïõ PHP/FI.
[1m16.7. ÔñÝ÷ïíôáò ôï PHP/FI áðü ôç ãñáììÞ åíôïëþí[0m
Áí ÷ôßóåôå ôç CGI Ýêäïóç ôïõ PHP/FI, ìðïñåßôå íá ôï ÷ñçóéìïðïéÞóåôå
áðü ôç ãñáììÞ åíôïëþí áðëÜ ãñÜöïíôáò: php.cgi filename üðïõ ôï
filename åßíáé ôï áñ÷åßï ðïõ èÝëåôå íá êÜíåôå parse. Ìðïñåßôå íá
äçìéïõñãÞóåôå åðßóçò standalone PHP/FI scripts ãñÜöïíôáò óôçí ðñþôç
ãñáììÞ ôïõ script óáò ôï åîÞò:
#!/usr/local/bin/php.cgi -q
Ôï "-q" áðáãïñåýåé ôçí åêôýðùóç ôùí HTTP headers. Ìðïñåßôå íá áöÞóåôå
Ýîù áõôÞ ôçí åðéëïãÞ áí èÝëåôå.
[1m17. Äéáóýíäåóç ìå PostgreSQL ìÝóù Python[0m
Ï Python åßíáé ìßá scripting ãëþóóá, áíôéêåéìåíïóôñáöÞò, óå ìïñöÞ
ìåôáöñáóôÞ (interpreted). Åíáò áðëüò óôç ÷ñÞóç (åýêïëç óýíôáîç, áðëÝò
êáé ðñïöáíåßò äçëþóåéò) êáé Ý÷åé ðïëëÝò åðåêôÜóåéò ãéá ôçí äçìéïõñãßá
ãñáöéêþí äéáóõíäÝóåùí (GUIs), åðéêïéíùíßá ìå ôï WWW, êëð. Åíáò Ýîõðíïò
web browser (ôýðïõ HotJava) âñßóêåôáé óå áíÜðôõîç (ÍïÝìâñéïò. 1995)
êáé áõôü èá áíïßîåé óôïõò ðñïãñáììáôéóôÝò ðïëëÝò ðüñôåò. Ï python
åßíáé ðíåõìáôéêÞò éäéïêôçóßáò ôïõ Stichting S Mathematisch Centrum,
Amsterdam. The Neverlands êáé åßíáé åëåýèåñçò áíáäéáíïìÞò.
Õðïóôçñßæåé äõíáìéêü öüñôùìá áíôéêåéìÝíùí, êëÜóåùí, modules, êáé
åîáéñÝóåùí (exceptions). ÐñïöáíÞò åßíáé ç ðñïóèÞêç äéáóõíäÝóåùí ìå
íÝåò âéâëéïèÞêåò ìÝóù êþäéêá C, ðñÜãìá ðïõ êÜíåé ôïí Python åýêïëá
êáôÜëëçëï ãéá éäéüìïñöåò ñõèìßóåéò.
Ï Python åßíáé ìéá scripting ãëþóóá õøçëïý åðéðÝäïõ ìå X interface.
Ï Python äéáíÝìåôáé ìå ôá Linux cdroms ðïõ ðåñéëáìâÜíïõí ôá
ðåñéóóüôåñï óôÜíôáñ Python modules, ìáæß ìå modules ãéá äéáóýíäåóç ìå
ôï óýíïëï Tix widget ãéá ôçí Tk.
To PyGreSQL åßíáé Ýíá python interface ãéá ôçí PostgreSQL. Åíóùìáôþíåé
ôçí âéâëéïèÞêç åñùôÞóåùí PostgreSQL ãéá íá åðéôñÝðåé ôçí åýêïëç ÷ñÞóç
ôùí ðáíßó÷õñùí äõíáôïôÞôùí ôçò PostgresSQL ìÝóá áðü Python scripts.
To PyGreSQL ãñÜöôçêå áðü ôïí D'Arcy J.M. Cain êáé ôïí Pascal Andre.
· Íåï site ôçò PyGreSQL <http://www.druid.net/pygresql/>
· Óõíôçñåßôáé áðü ôïí D'Arcy at <http://www.druid.net/~darcy/>
· Ôï ðáëéü site åßíáé óôï
<ftp://ftp.via.ecp.fr/pub/python/contrib/Database/PyGres95.README >
· D'Arcy J.M. Cain darcy@druid.net
· Pascal Andre andre@chimay.via.ecp.fr
· Pascal Andre andre@via.ecp.fr
[1m17.1. Ðïý ìðïñþ íá âñù ôï PyGres ;[0m
Ôá home sites ôùí äéáöïñåôéêþí ðáêÝôùí åßíáé:
· Python
<ftp://ftp.python.org:/pub/www.python.org/1.5/python1.5b2.tar.gz>
· PyGreSQL <ftp://ftp.druid.net/pub/distrib/PyGreSQL-2.1.tgz>
· Old site
<ftp://ftp.via.ecp.fr/pub/python/contrib/Database/PyGres95-1.0b.tar.gz
>
Èá ðñÝðåé íá øÜîåôå íá âñåßôå êÜðïéï mirror site êïíôÜ óôçí ðåñéï÷Þ
óáò. Áíáöåñèåßôå óôá ðëçñïöïñéáêÜ áñ÷åßá ãéá ôï ðïý èá âñåßôå áõôÜ
ôá sites. Ôï PyGres95 èá ðñÝðåé íá âñßóêåôáé óôïõò êáôáëüãïõò
contrib ôùí sites ôùí Python êáé PostgreSQL.
[1m17.2. Ðëçñïöïñßåò êáé õðïóôÞñéîç[0m
Áí ÷ñåéÜæåóôå ðåñéóóüôåñåò ðëçñïöïñßåò ãéá áõôÜ ôá ðáêÝôá,
åðéóêåöôåßôå ðáñáêáëþ ôá web sites ôïõò:
· Python : <http://www.python.org/>
· PostgreSQL :
<http://epoch.cs.berkeley.edu:8000/postgres95/index.html>
· PyGreSQL <ftp://ftp.druid.net/pub/distrib/PyGreSQL-2.1.tgz>
· Old site PyGreSQL :
<http://www.via.ecp.fr/via/products/pygres.html>
Ãéá õðïóôÞñéîç :
· Ëßóôá áëëçëïãñáößáò ãéá PyGreSQL. Ìðïñåßôå íá åããñáöåßôå óôÝëíïíôáò
ìÞíõìá óôï majordomo@vex.net ìå ôçí ãñáììÞ "subscribe pygresql
name@domain" óôï óþìá ôïõ ìçíýìáôïò áíôéêáèéóôþíôáò ôï
"name@domain" ìå ôçí äéêÞ óáò çëåêôñïíéêÞ äéåýèõíóç áëëçëïãñáößáò.
· Newsgroup for Python : newsgroup comp.lang.python
· PyGreSQL : åðéêïéíùíÞóôå ìå ôïí Andre óôï andre@via.ecp.fr ãéá
áíáöïñÝò óöáëìÜôùí, éäåþí, ó÷ïëåßùí
[1m18. Åðéêïéíùíßá ìåôáîý PostgreSQL êáé WWW - WDB-P95[0m
[1m18.1. Ó÷åôéêÜ ìå ôï wdb-p95[0m
WDB-P95 - ¸íá Web interface ãéá âÜóåéò PostgreSQL áðü ôïí J. Douglas
Dunlop Âñßóêåôáé óôï
· ÍÝï WDB áðü ôïí J Rowe âñßóêåôáé óôï
<http://www.lava.net/beowulf/programming/wdb>
· ÍÝåò åêäüóåéò ôïõ WWW-WDB óôï <http://www.eol.ists.ca/~dunlop/wdb-
p95/>
· Ãéá åñùôÞóåéò Þ ãéá åããñáöÞ óôéò Ëßóôåò Áëëçëïãñáößáò,
åðéêïéíùíÞóôå ìå ôïí dunlop@eol.ists.ca
Åßíáé ìéá ôñïðïðïéçìÝíç Ýêäïóç ôïõ wdb-1.3a2 ðïõ ðáñÝ÷åé ìéá óýíäåóç
óôï WWW ãéá ôçí PostgreSQL. ÁõôÞ ç Ýêäïóç áðáéôåß åðßóçò Ýíá Browser
éêáíü íá ÷åéñßæåôáé ðßíáêåò HTML ãéá ôçí Ýîïäï óå ðßíáêåò (tabular
output). Áõôü äåí áðáéôåßôáé áðü ôï áñ÷éêü wdb êáé ìðïñåß íá
åðáíáöåñèåß óôçí ðáëéÜ ìïñöÞ ôïõ ó÷åôéêÜ åýêïëá.
Ìðïñåßôå íá äïêéìÜóåôå ôá CASI Tape êáé Image Query. Ìðïñåßôå íá
ñßîåôå ìéá ãñÞãïñç ìáôéÜ óôï Form Definition File (FDF) ðïõ
÷ñçóéìïðïßçóá ãéá íá öôéÜîù ôá CASI Tape êáé Image Query åðßóçò, ðïõ
ðåñéëáìâÜíåé Ýíá JOIN 2 ðéíÜêùí.
ÁõôÞ ç Ýêäïóç ðåñéÝ÷åé üëá ôá áðáñáßôçôá áñ÷åßá ãéá ôçí åãêáôÜóôáóç
êáé åêôÝëåóç ôïõ WDB-P95 óáí äéáóýíäåóç ìå ôéò PostgreSQL âÜóåéò óáò.
Ç ìåôáöïñÜ ôïõ óõóôÞìáôïò óå Üëëç âÜóç èá ðñÝðåé íá åßíáé ó÷åôéêÜ
åýêïëç - õðü ôçí ðñïûðüèåóç ðùò õðïóôçñßæåé óôÜíôáñ SQL êáé Ý÷åé
interface óå Perl.
[1m18.2. Åßíáé áðáñáßôçôï ï äéáêïìéóôÞò ôçò PostgreSQL, ôï pgperl, êáé[0m
[1môï httpd íá åßíáé óôïí ßäéï host;[0m
Ï÷é - ï äéáêïìéóôÞò ôçò PostgreSQL äéáêïìéóôÞò äå ÷ñåéÜæåôáé íá åßíáé
óôï ßäéï host. Ôï WDB-P95 åðåéäÞ êáëåßôáé áðü ôïí http äáßìïíá, ðñÝðåé
íá åßíáé óôï ßäéï host - êáé êáèþò ôï WDB-P95 ãñÜöôçêå ãéá íá
÷ñçóéìïðïéåß ôï Pg.pm - ôï pgperl ðñÝðåé íá åßíáé óôï ßäéï host
åðßóçò. Ôï Pgperl ãñÜöôçêå ÷ñçóéìïðïéþíôáò ôç âéâëéïèÞêç libpq, Ýôóé
ìðïñåß íá Ý÷åé ðñüóâáóç óå ïðïéïäÞðïôå äéáêïìéóôÞ PostgreSQL
ïðïõäÞðïôå óôï äßêôõï, üðùò ïðïéïóäÞðïôå Üëëïò ðåëÜôçò PostgreSQL.
¼ðùò öáßíåôáé ðáñáêÜôù
(WWW Client (Netscape)) => (HTTP Server (NCSA's http) + WDB-P95 +
pgperl + libpq)=> (PostgreSQL server)
Ïé ðáñåíèÝóåéò () áíáðáñéóôïýí ìç÷áíÞìáôá.
ÊÜèå ìç÷Üíçìá ìðïñåß íá åßíáé äéáöïñåôéêïý ôýðïõ : NT, SUN, HP, ...
áëëÜ ÷ñåéÜæåóôå ôç âéâëéïèÞêç äéáóýíäåóçò libpq ãéá ôïí ôýðï
ìç÷áíÞìáôïò ðïõ óêïðåýåôå íá ÷ñçóéìïðïéÞóåôå ôï WDB-P95, ãéá íá
ìåôáãëùôôßóåôå ôï pgperl. (Ôï óýóôçìá ó÷åäéÜóôçêå ãéá íá ÷ñçóéìïðïéåß
HTML ðßíáêåò ãé' áõôü åßíáé ðñïôéìüôåñïò Ýíáò ðñüóöáôïò WWW client).
[1m19. ÐñïãñáììáôéóôéêÝò äéáóõíäÝóåéò ãéá "C", "C++", ESQL/C êáé[0m
[1mÄõáäéêïß ÔåëåóôÝò ãéá ôçí PostgreSQL[0m
[1m19.1. Äéáóýíäåóç ãëþóóáò "C" ìå ôçí PostgreSQL[0m
ÓõìðåñéëáìâÜíåôáé óôç äéáíïìÞ êáé ïíïìÜæåôáé 'libpq'. Åßíáé ðáñüìïéï
ìå ôá Oracle OCI, Sybase DB-lib êáé ôéò âéâëéïèÞêåò Informix CLI .
[1m19.2. Interface ãëþóóáò "C++" ãéá ôçí PostgreSQL[0m
ÓõìðåñéëáìâÜíåôáé óôç äéáíïìÞ êáé ïíïìÜæåôáé 'libpq++'.
[1m19.3. ESQL/C ãéá PostgreSQL[0m
O 'ÅíóùìáôùìÝíïò ðñïìåôáãëùôôéóôÞò C' ãéá ôçí PostgreSQL, ESQL/C åßíáé
üðùò ôï Oracle Pro*C, êáé ôï Informix ESQL/C. To PostgreSQL ESQL/C
åßíáé Ýíá ðñïãñáììáôéóôéêü ðåñéâÜëëïí äéáóýíäåóçò (API) ìåSQL, ðïõ
åðéôñÝðåé óôïí ðñïãñáììáôéóôÞ C íá äçìéïõñãåß åéäéêÝò åöáñìïãÝò ìå
äõíáôüôçôåò äéá÷åßñéóçò ôçò âÜóçò äåäïìÝíùí. Óáò åðéôñÝðåé íá
÷ñçóéìïðïéåßôå ìéá ãëþóóá ôñßôçò ãåíåÜò ìå ôçí ïðïßá åßóáóôå
åîïéêåéùìÝíïò êáé íá åêìåôáëëåýåóôå ðáñÜëëçëá êáé ôá ðëåïíåêôÞìáôá ôçò
ÄïìçìÝíçò Ãëþóóáò ÅñùôÞóåùí (SQL).
To ESQL/C áðïôåëåßôáé áðü ôá ðáñáêÜôù êïììÜôéá ëïãéóìéêïý:
· Ôéò âéâëéïèÞêåò ESQL/C ìå óõíáñôÞóåéò C ðïõ äßíïõí ðñüóâáóç ðñïò
ôïí äéáêïìéóôÞ ôçò âÜóçò äåäïìÝíùí (database server).
· Ôá áñ÷åßá åðéêåöáëßäùí ôïõ ESQL/C ðïõ äßíïõí ôïõò ïñéóìïýò ãéá ôéò
äïìÝò äåäïìÝíùí, ôéò óôáèåñÝò, êáé ìáêñïåíôïëÝò ÷ñÞóéìåò ãéá ôï
ðñüãñáììá ESQL/C.
· Ï ðñïåðåîåñãáóôÞò ESQL/C, åßíáé Ýíáò ðñïåðåîåñãáóôÞò ðçãáßïõ êþäéêá
ðïõ ìåôáôñÝðåé Ýíá C áñ÷åßï ðïõ ðåñéÝ÷åé åíôïëÝò SQL óå Ýíá
åêôåëÝóéìï áñ÷åßï.
Âñßóêåôáé óôï
· Ç ESQL/C ãéá ôçí PostgreSQL ðåñéëáìâÜíåôáé óôéò äéÜöïñåò äéáíïìÝò.
· Ôï êýñéï site åßíáé <ftp://ftp.lysator.liu.se/pub/linus>
· Email : linus@epact.se
[1m19.4. Äõáäéêïß ÔåëåóôÝò ãéá ôçí PostgreSQL[0m
Ïé äõáäéêïß ôåëåóôÝò ãñÜöôçêáí áðü ôïí Nicolas Moldavsky
· nico@overnet.com.ar
Ïé "C" óõíáñôÞóåéò ðïõ õëïðïéïýí ôïõò äõáäéêïýò ôåëåóôÝò (AND, OR,
XOR, óõìðëÞñùìá ùò ðñïò 2) óå pgsql. Ìðïñåßôå íá ôá êáôåâÜóåôå ìå
anonymous FTP áðü ôï
· <ftp://ftp.overnet.com.ar/pub/utils/linux/bitpgsql.tgz>
ÐåñéëáìâÜíåôáé Makefile ãéá Linux.
[1m20. Japanese Kanji Êþäéêáò ãéá ôçí PostgreSQL[0m
Âñßóêåôáé óôï ðáñáêÜôù site
· <ftp://ftp.sra.co.jp/pub/cmd/postgres/>
[1m21. ÌåôáöïñÜ ôçò PostgreSQL óå Windows 95/Windows NT[0m
Ç ìåôáöïñÜ óôá Windows 95/Windows NT åßíáé óå åîÝëéîç. Ç ìåôáöïñÜ
ãßíåôáé ÷ñçóéìïðïéþíôáò ôï gcc êáé ôï gmake ãéá Win NT/95. Ãéá íá
ìåôáãëùôôßóïõìå ôïí ðçãáßï êþäéêá óå win32 ÷ñçóéìïðïéïýìå ôï ðñüãñáììá
gnu-win32. Ôï GNU gcc åßíáé äéáèÝóéìï ãéá win32. Ðçãáßíåôå óôï site -
· <http://www.cygnus.com/misc/gnu-win32>
êáé êáôåâÜóôå ôï áñ÷åßï cdk.exe (áõôï-áðïóõìðéåæüìåíï áñ÷åßï ãéá
gnu-win32)
Ç ìåôáöïñÜ ìðïñåß åðßóçò íá ãßíåé ÷ñçóéìïðïéþíôáò ôï áêüëïõèï åñãáëåßï
"Unix-Emulator on NT" áðü ôï
· <http://www.softway.com>
[1m22. Ëßóôåò áëëçëïãñáößáò[0m
[1m22.1. ÁðïêôÞóôå Ýíá äùñåÜí ëïãáñéáóìü e-mail[0m
ÅëÝãîôå ôéò äùñåÜí ðñïóöïñÝò - áðïêôÞóôå äùñåÜí ëïãáñéáóìïýò e-mail
áðü ôá
· Yahoo <http://www.yahoo.com> êëéêÜñåôå óôï e-mail
· Lycos <http://www.lycos.com> êëéêÜñåôå óôïõò íÝïõò ëïãáñéáóìïýò e-
mail (new email accounts)
· hotmail <http://www.hotmail.com> êëéêÜñåôå óôïõò íÝïõò
ëïãáñéáóìïýò e-mail (new email accounts)
Ãñáöôåßôå óôç ëßóôá áëëçëïãñáößáò ôçò PostgreSQL êáé ôï Yahoo óáò
äßíåé ôçí åðéðëÝïí äõíáôüôçôá íá äçìéïõñãÞóåôå Ýíá îå÷ùñéóôü öÜêåëï
ãéá ôá e-mails ôçò PostgreSQL, Ýôóé þóôå ôá íá ìçí áíáêáôþíïíôáé ìå
ôá Üëëá ðñïóùðéêÜ óáò e-mail. ÅðéëÝîôå ôï ìåíïý Email- > Options- >
Filters êáé äéáëÝîôå îå÷ùñéóôü öÜêåëï ãéá email. Ìå áõôü ôï
ëïãáñéáóìü e-mail ìðïñåßôå íá ðáßñíåôå Þ íá óôÝëíåôå mail áðü
ïðïõäÞðïôå óôïí êüóìï åöüóïí Ý÷åôå ðñüóâáóç óå web óåëßäá.
Áí Ý÷åôå êÜðïéï Üëëï e-mail, ìðïñåßôå íá ÷ñçóéìïðïéÞóåôå ôçí åðéëïãÞ
"Mail Filters" ãéá íá ëáìâÜíåôå áõôüìáôá ôá mails ôçò PostgreSQL óå
îå÷ùñéóôü öÜêåëï. Ìå áõôü ôïí ôñüðï ôá mails óáò åßíáé êáëýôåñá
ïñãáíùìÝíá êáé áðïöåýãåôå êáé ôï áíáêÜôåìá ôoõò.
[1m22.2. ÁããëéêÞ Ëßóôá Áëëçëïãñáößáò[0m
Äåßôå ôéò Ëßóôåò Áëëçëïãñáößáò óôçí êåíôñéêÞ óåëßäá óôï web óôï :
· <http://www.postgresql.org/>
· ÅñùôÞóåéò ìÝóù Email óôï: pgsql-questions@postgresql.org
· Developers pgsql-hackers@postgresql.org
· Port specific questions pgsql-ports@postgresql.org
· Documentation questions pgsql-docs@postgresql.org
Èá ëÜâåôå áðáíôÞóåéò ìÝóù e-mail óå ëéãüôåñï áðü ìßá ìÝñá!!
Ìðïñåßôå íá ãñáöôåßôå åðßóçò óå ëßóôåò áëëçëïãñáößáò. Äåßôå åðßóçò ôï
ðáñáðÜíù ôìÞìá 'ÁðïêôÞóôå Ýíá äùñåÜí ëïãáñéáóìü e-mail'. Ãéá íá
ãñáöôåßôå Þ íá îåãñáöôåßôå áðü ìéá ëßóôá, óôåßëôå mail óôá
· pgsql-questions-request@postgresql.org
· pgsql-hackers-request@postgresql.org
· pgsql-ports-request@postgresql.org
· pgsql-docs-request@postgresql.org
Ôï êõñßùò ôìÞìá (body) ôïõ ìçíýìáôïò èá ðåñéÝ÷åé ìüíï ôçí áêüëïõèç
ãñáììÞ
subscribe
(Þ)
unsubscribe
[1m22.3. Áñ÷åßï ôçò Ëßóôáò Áëëçëïãñáößáò[0m
Êñáôåßôáé áñ÷åßï ôùí ëéóôþí áëëçëïãñáößáò óå html ìïñöÞ óôéò ðáñáêÜôù
äéåõèýíóåéò -
· ÄéáèÝóéìç ëßóôá ìå âÜóç ôéò äéåõèýíóåéò ìÝóù MHonarc êáé WWW óôï
<http://www.postgresql.org/mhonarc/pgsql-questions>
· <ftp://ftp.postgresql.org> óôïí êáôÜëïãï /pub/majordomo
[1m22.4. ÉóðáíéêÞ Ëßóôá Áëëçëïãñáößáò[0m
ÕðÜñ÷åé ôþñá êáé ìéá "áíåðßóçìç" ëßóôá ãéá ôçí postgreSQL óôá
éóðáíéêÜ. Äåßôå åðßóçò ôï ðáñáðÜíù ôìÞìá 'ÄùñåÜí Ëïãáñéáóìüò ãéá íá
ïñãáíþóåôå ôá e-mails ôçò PostgreSQL' . Ãéá íá åããñáöåßôå, ðñÝðåé íá
óôåßëåôå Ýíá ìÞíõìá óôï:
· majordomo@tlali.iztacala.unam.mx
Ôï êõñßùò ôìÞìá (body) ôïõ ìçíýìáôïò èá ðåñéÝ÷åé ìüíï ôçí áêüëïõèç
ãñáììÞ:
inscripcion pgsql-ayuda
[1m23. Ôåêìçñßùóç êáé Âéâëéïãñáößá[0m
[1m23.1. Ïäçãïß åêìÜèçóçò êáé Åã÷åéñßäéá[0m
Ôá ðáñáêÜôù óõìðåñéëáìâÜíïíôáé óôç äéáíïìÞ ôçò PostgreSQL óå ìïñöÞ
postscript êáé óå unix óåëßäåò âïçèåßáò (man-pages). Áí Ý÷åôå
ðñüóâáóç óôï internet, ìðïñåßôå íá âñåßôå ôá êåßìåíá ðïõ áíáöÝñïíôáé
ðáñáêÜôù óôï <http://www.postgresql.org/docs>
· "Ïäçãüò ÅãêáôÜóôáóçò"
· "Ïäçãüò ÷ñÞóçò" ãéá ôçí PostgreSQL
· "Ïäçãüò áíÜðôõîçò-õëïðïßçóçò" ìå ëåðôïìÝñåéåò ãéá ôéò åóùôåñéêÝò
ëåéôïõñãßåò ôçò PostgreSQL.
· Online åã÷åéñßäéá.
· Online åã÷åéñßäéá óå HTML ìïñöÞ.
· Åðßóçò, åã÷åéñßäéá óå ìïñöÞ Postscript ãéá åêôýðùóç.
[1m23.2. Online Ôåêìçñßùóç[0m
· Ëßóôá êáé ðåñéãñáöÞ ôùí ðñïêáèïñéóìÝíùí ôýðùí äåäïìÝíùí êáé
ôåëåóôþí
Åßíáé ôìÞìá ôùí åíôïëþí PSQL óôçí Ýêäïóç 6.4.
· Ëßóôá ôùí õðïóôçñéæüìåíùí SQL ëÝîåùí êëåéäéÜ (keywords)
ÕðÜñ÷åé Ýíá script óôïí êáôÜëïãï /tools ãéá íá ôï êÜíåôå áõôü
· Ëßóôåò ôùí õðïóôçñéæüìåíùí åíôïëþí -
×ñçóéìïðïéÞóôå ôçí åíôïëÞ psql \h
· ÂáóéêÝò Ýííïéåò ó÷åóéáêÞò âÜóçò äåäïìÝíùí ãéá PostgreSQL
(õëïðïßçóç) êáé áñêåôÜ online ðáñáäåßãìáôá (åñùôÞóåéò) -
ÊïéôÜîôå óôá regression tests óôï src/test. Åêåß èá âñåßôå ôïõò êáôáëüãïõò
regress/sql êáé suite/*.sql.
· Ïäçãüò åêìÜèçóçò ãéá ôçí PostgreSQL.
Èá âñåßôå SQL scripts ãéá åêìÜèçóç ôçò SQL óôïí êáôÜëïãï src/tutorial
Äåßôå åðßóçò ôï "Ïäçãüò åêìÜèçóçò SQL ãéá áñ÷Üñéïõò" óôï Appendix B
áõôïý ôïõ êåéìÝíïõ ``''
[1m23.3. ×ñÞóéìç Âéâëéïãñáößá ÁíáöïñÜò[0m
· "Understanding the New SQL: A Complete Guide" - áðü ôïõò Jim Melton
êáé Alan R.Simon
Ôï Morgan Kaufman Publisher åßíáé Ýíá áðü ôá êáëýôåñá âéâëßá ãéá SQL. Áó÷ïëåßôáé ìå ôçí SQL92.
· "A Guide to THE SQL STANDARD" - áðü ôïí C.J.Date
Ç åôáéñåßá Addison-Wesley Publishing Ý÷åé åðßóçò ðïëý êáëÜ âéâëßá. Ðïëý äçìïöéëÞ âéâëßá ãéá SQL.
· SQL - The Standard Handbook, ÍïÝìâñéïò 1992
Stephen Cannan êáé Gerard Otten
McGraw-Hill Book Company Europe , Berkshire, SL6 2QL, England
· SQL Instant Reference, 1993
Martin Gruber, Technical Editor: Joe Celko
SYBEX Inc. 2021 Challenger Drive Alameda, CA 94501
· C.J.Date, "An introduction to Database Systems" (6th Edition),
Addison-Wesley, 1995, ISBN 0-201-82458-2
Áõôü ôï âéâëßï åßíáé ç Âßâëïò ôçò Äéá÷åßñéóçò ÓõóôçìÜôùí âÜóåùí ÄåäïìÝíùí.
ÐåñéÝ÷åé ðëçñïöïñßåò ãéá êáíïíéêïðïßçóç, SQL, recovery, concurrency, áóöÜëåéá,
integrity, êáé extensions óôï áñ÷éêü ó÷åóéáêü ìïíôÝëï, ôñÝ÷ïíôá èÝìáôá
üðùò client/server óõóôÞìáôá êáé ÁíôéêåéìåíïóôñáöÞ ìïíôÝëá. ÐïëëÝò
áíáöïñÝò óõìðåñéëáìâÜíïíôáé ãéá üóïõò èÝëïõí íá ìÜèïõí ðåñéóóüôåñá. Ôï óõíéóôïýìå óôïõò ðåñéóóüôåñïõò ÷ñÞóôåò.
· Stefan Stanczyk, "Theory êáé Practice of Relational Databases", UCL
Press Ltd, 1990, ISBN 1-857-28232-9
ÐåñéÝ÷åé ëåðôïìÝñåéåò ìå èåùñßá ó÷åóéáêþí âÜóåùí, ó÷åóéáêÞ Üëãåâñá, calculus
êáé êáíïíéêïðïßçóç. ÁëëÜ äåí êáëýðôåé èÝìáôá ôïõ ðñáãìáôéêïý êüóìïõ êáé ðáñáäåßãìáôá ðéï óýíèåôá. Ôï óõíéóôïýìå óôïõò ðåñéóóüôåñïõò ÷ñÞóôåò.
· "The Practical SQL Handbook" Ôñßôç ¸êäïóç, Addison Wesley
Developers Press ISBN 0-201-44787-8
Ôï óõíéóôïýìå óôïõò ðåñéóóüôåñïõò ÷ñÞóôåò.
· Michael Stonebraker, "Readings in Database Systems", Morgan
Kaufmann, 1988, ISBN 0-934613-65-6
Ôï âéâëßï åßíáé ìéá óõëëïãÞ áðü ÷áñôéÜ ðïõ Ý÷ïõí äçìïóéåõôåß üëá ôá ÷ñüíéá ó÷åôéêÜ ìå âÜóåéò. Äåí åßíáé ãéá ôïí áðëü ÷ñÞóôç áëëÜ åßíáé ìéá êáëÞ áíáöïñÜ ãéá ðñï÷ùñçìÝíïõò (ìåôáðôõ÷éáêïýò) öïéôçôÝò Þ ðñïãñáììáôéóôÝò óõóôçìÜôùí âÜóåùí äåäïìÝíùí.
· C.J.Date, "Relational Database - Selected Readings", Addison-
Wesley, 1986, ISBN 0-201-14196-5
Ôï âéâëßï åßíáé ìéá óõëëïãÞ áðü ÷áñôéÜ ðïõ Ý÷ïõí äçìïóéåõôåß üëá ôá ÷ñüíéá ó÷åôéêÜ ìå âÜóåéò. Äåí åßíáé ãéá ôïí áðëü ÷ñÞóôç áëëÜ åßíáé ìéá êáëÞ áíáöïñÜ ãéá ðñï÷ùñçìÝíïõò (ìåôáðôõ÷éáêïýò) öïéôçôÝò Þ ðñïãñáììáôéóôÝò óõóôçìÜôùí âÜóåùí äåäïìÝíùí.
· Nick Ryan êáé Dan Smith, "Database Systems Engineering",
International Thomson Computer Press, 1995, ISBN 1-85032-115-9
Áõôü ôï âéâëßï Ý÷åé ëåðôïìÝñåéåò ãéá ìåèüäïõò ðñüóâáóçò, êáé ôå÷íéêÝò áðïèÞêåõóçò.
· Bipin C. Desai, "An introduction to Database Systems", West
Publishing Co., 1990, ISBN 0-314-66771-7
Äåí åßíáé ãéá ôïí áðëü ÷ñÞóôç áëëÜ åßíáé ìéá êáëÞ áíáöïñÜ ãéá ðñï÷ùñçìÝíïõò (ìåôáðôõ÷éáêïýò) öïéôçôÝò Þ ðñïãñáììáôéóôÝò óõóôçìÜôùí âÜóåùí äåäïìÝíùí.
· Joe Celko "INSTANT SQL Programming"
Wrox Press Ltd.
Unit 16, 20 James Road, Tyseley
Birmingham, B11 2BA, England
1995
· Michael Gorman "Database Management Systems: Understanding êáé
Applying Database"
Technology
QED êáé John Wiley
1991
· Michael Gorman "Enterprise Database for a Client/Server
Environment" QED êáé John Wiley
ÐáñïõóéÜæåé ôéò áðáéôÞóåéò ãéá íá öôéÜîåôå client/server åöáñìïãÝò âÜóåùí
ìÝóù repository ìåôáìïíôÝëùí êáé ôçò ÷ñÞóçò ANSI óôÜíôáñ SQL
1993
ÅêáôïíôÜäåò Üëëïé ôßôëïé åßíáé äéáèÝóéìïé ãéá SQL ! ÊïéôÜîôå óôá
âéâëéïðùëåßá.
[1m23.4. Êåßìåíá ðñïäéáãñáöþí ANSI/ISO SQL - SQL 1992, SQL 1998[0m
Ìðïñåßôå íá âñåßôå êåßìåíá ðñïäéáãñáöþí ANSI/ISO SQL óôá ðáñáêÜôù
sites -
· <http://www.naiua.org/std-orgs.html>
· <http://www.ansi.org/docs> êáé êëéêÜñåôå óôï áñ÷åßï cat_c.html êáé
øÜîôå ãéá "Database SQL"
· SQL92 standard <http://www.jcc.com> êáé êëéêÜñåôå óôï áñ÷åßï
sql_stnd.html
· ANSI/ISO SQL ðñïäéáãñáöÝò
<http://www.contrib.andrew.cmu.edu/~shadow/sql.html> Åäþ èá âñåßôå
åã÷åéñßäéï ãéá SQL.
[1m23.5. Óýíôáîç ANSI/ISO SQL 1992[0m
Äåßôå ôï Appendix A áõôïý ôïõ êåéìÝíïõ ``''
[1m23.6. Óýíôáîç ANSI/ISO SQL 1998[0m
Ïé ðñïäéáãñáöÝò SQL 1998 (SQL 3) åßíáé áêüìç õðü áíÜðôõîç. Äåßôå ôï
'Electronic Access to the SQL3 Working Draft' áõôïý ôïõ êåéìÝíïõ óôï
``''
[1m23.7. Ïäçãüò åêìÜèçóçò SQL ãéá áñ÷Üñéïõò[0m
Äåßôå ôï Appendix B áõôïý ôïõ êåéìÝíïõ ``''
[1m23.8. ÐñïóùñéíÞ åðÝêôáóç (extension) óôï SQL92[0m
· Êåßìåíï ãéá ðñïóùñéíÞ åðÝêôáóç SQL-92
<ftp://FTP.cs.arizona.edu/tsql/tsql2/>
· ÐñïóùñéíÝò ðñïäéáãñáöÝò SQL-3
<ftp://FTP.cs.arizona.edu/tsql/tsql2/sql3/>
Ï êáôÜëïãïò ðåñéÝ÷åé ôéò ðñïäéáãñáöÝò ôçò ãëþóóáò ãéá ôçí ðñïóùñéíÞ
åðÝêôáóç óôç óôÜíôáñ ãëþóóá SQL-92. ÁõôÞ ç íÝá ãëþóóá ïíïìÜæåôáé
TSQL2.
Ïé ðñïäéáãñáöÝò ôçò ãëþóóáò ðïõ ðáñïõóéÜæïíôáé åäþ åßíáé ç ôåëéêÞ
Ýêäïóç ôçò ãëþóóáò.
Ç áëëçëïãñáößá ìðïñåß íá óôáëåß óôïí ðñüåäñï ôïõ TSQL2 Language Design
Committee, Richard T.Snodgrass, Department of Computer Science,
University of Arizona, Tucson, AZ 85721,
· rts@cs.arizona.edu
Ïé èõãáôñéêÝò êáé ïé äéåõèýíóåéò e-mail ôùí ìåëþí ôïõ TSQL2
Language Design Committee ìðïñïýí íá âñåèïýí óå îå÷ùñéóôü ôìÞìá óôï
ôÝëïò ôùí ðñïäéáãñáöþí ôçò ãëþóóáò.
Ôá ðåñéå÷üìåíá áõôïý ôïõ êáôáëüãïõ åßíáé üðùò ðáñïõóéÜæïíôáé ðáñáêÜôù.
spec.dvi,.ps ÐñïäéáãñáöÝò Ãëþóóáò TSQL2, åêäüèçêå ôï ÓåðôÝìâñéï ôïõ
1994
bookspec.ps ÐñïäéáãñáöÝò ôçò Ãëþóóáò TSQL2, üðùò åìöáíßóôçêáí óôï
âéâëßï TSQL2, ðïõ åêäüèçêå ôï ÓåðôÝìâñéï ôïõ 1995 (äåßôå ðáñáêÜôù).
sql3 áëëáãÞ ôùí ðñïôÜóåùí ðïõ õðïâëÞèçêáí óôéò åðéôñïðÝò
ANSI êáé ISO SQL3.
Ìáæß ìå ôéò ðñïäéáãñáöÝò ôçò ãëþóóáò Ý÷åé óõó÷åôéóôåß ìéá óõëëïãÞ áðü
ó÷üëéá ðïõ áöïñïýí óå áðïöÜóåéò ó÷åäéáóìïý, ðáñï÷Þ ðáñáäåéãìÜôùí, êáé
áðüøåéò ãéá ôï ðþò ìðïñåß íá õëïðïéçèåß ç ãëþóóá. ÁõôÜ ôá ó÷üëéá Þôáí
áñ÷éêÜ ðñïôÜóåéò óôçí åðéôñïðÞ ôïõ TSQL2 Language Design. Ôþñá
åîõðçñåôïýí Ýíá óõãêåêñéìÝíï óêïðü: íá ðáñÝ÷ïõí ðáñáäåßãìáôá ôïõ üôé
Ý÷åé öôéá÷ôåß, ùèÞóïõí ôéò ðïëëÝò áðïöÜóåéò ðïõ ðÜñèçêáí êáôÜ ôï
ó÷åäéáóìü ôçò ãëþóóáò, êáé íá óõãêñßíïõí ôçí TSQL2 ìå ðïëëÝò Üëëåò
ðñïôÜóåéò ôçò ãëþóóáò ðïõ Ý÷ïõí ãßíåé ôá ôçí ôåëåõôáßá äåêáðåíôáåôßá.
Èá ðñÝðåé íá äïèåß Ýìöáóç üôé áõôÜ ôá ó÷üëéá äåí åßíáé ôìÞìá ôùí
ðñïäéáãñáöþí ôçò ãëþóóáò TSQL2, áëëÜ ôç óõìðëçñþíïõí êáé áíáðôýóóïõí
ìå âÜóç áõôÜ. Ïé êáôÜëëçëåò ðñïäéáãñáöÝò ôçò ãëþóóáò åßíáé ç ôåëåõôáßá
ëÝîç óôçí TSQL2.
Ôá ó÷üëéá, ìáæß ìå ôéò ðñïäéáãñáöÝò ôçò ãëþóóáò , áñêåôïß äåßêôåò
(indexes), êáé Üëëï õëéêü õðïóôÞñéîçò, Ý÷ïõí åêäïèåß óå Ýíá âéâëßï:
Snodgrass, R.T., editor, The TSQL2 Temporal Query Language, Kluwer
Academic Publishers, 1995, 674+xxiv óåëßäåò.
Ïé êñéôéêÝò åìöáíßæïíôáé óôï âéâëßï óå ìéá óõíôïìåõìÝíç ìïñöÞ. Ïé
êñéôéêÝò ðáñÝ÷ïíôáé ðëÞñåéò óå áõôüí êáôÜëïãï óôï áñ÷åßï eval.ps
Ôï áñ÷åßï tl2tsql2.pl åßíáé Ýíá ðñüãñáììá óå prolog ðïõ ìåôáöñÜæåé ôçí
åðéôñåðüìåíç ðñïóùñéíÞ ëïãéêÞ óå TSQL2. Áõôü ôï ðñüãñáììá ãñÜöôçêå áðü
ôïí Michael Boehlen
· boehlen@iesd.auc.dk
Ìðïñåßôå íá åðéêïéíùíÞóåôå ìáæß ôïõ ãéá Ýíá paper ðïõ ðåñéãñÜöåé
áõôÞ ôç ìåôÜöñáóç. Áõôü åßíáé ìÜëëïí ìéá dated Ýêäïóç ôïõ
ðñïãñÜììáôïò. Íåþôåñåò åêäüóåéò åßíáé äéáèÝóéìåò óôï
· <http://www.cs.auc.dk/general/DBS/tdb/TimeCenter/Software>
(ôá óõóôÞìáôá TimeDB êáé Tiger).
[1m23.9. ÔìÞìá 0 - Áðïêôþíôáò ôá êåßìåíá ISO/ANSI SQL[0m
Áõôü ôï êåßìåíï óáò äåß÷íåé ðþò íá áðïêôÞóåôå (íüìéìá) Ýíá áíôßãñáöï
ôïõ ðñïôýðïõ SQL-92 êáé ôïõ "ôñÝ÷ïíôïò" SQL3 Working Draft.
Óôï ANSI ðñüôõðï Ý÷åé ðíåõìáôéêÜ äéêáéþìáôá ç ANSI, óôï ðñüôõðï ISO ç
ISO.
ÕðÜñ÷ïõí äýï (2) ôñÝ÷ïíôá ðñüôõðá SQL, ç äçìïóßåõóç ANSI êáé ç
äçìïóßåõóç ISO. Ôá äýï áõôÜ ðñüôõðá åßíáé ïëüéäéá ëÝîç ðñïò ëÝîç åêôüò
áðü ôåôñéììÝíá æçôÞìáôá üðùò ï ôßôëïò ôïõ êåéìÝíïõ, ïé åðéêåöáëßäåò
ôçò óåëßäáò, ç öñÜóç "International Standard" áíôß ãéá "American
Standard", êáé ëïéðÜ.
ÁãïñÜæïíôáò ôï ðñüôõðï SQL-92
Ôï ðñüôõðï ISO standard, ISO/IEC 9075:1992, Information Technology -
Database Languages - SQL, åßíáé äéáèÝóéìï (ÌÜñôéïò, 1993) óôï ANSI :
American National Standards Institute
1430 Broadway
New York, NY 10018 (USA)
Phone (sales): +1.212.642.4900
êáé êïóôßæåé US$230.00. H ANSI Ýêäïóç, ANSI X3.135-1992, American
National Standard ãéá ÓõóôÞìáôá Ðëçñïöïñéþí - Database Language SQL,
äåí Þôáí äéáèÝóéìï ðñïò ðþëçóç üôáí ãñÜöôçêå áõôü ôï êåßìåíï, áëëÜ
áíáìåíüôáí íá åßíáé äéáèÝóéìï ìåôáîý ôÝëç Ìáñôßïõ êáé áñ÷Ýò Ìáúïõ,
1993). Ôï êüóôïò ôïõ áíáìÝíåôáé ãýñù óôá US$225.00.
Áí áãïñÜóåôå êÜðïéï áðü ôá êåßìåíá áðü ôï ANSI, èá Ý÷åôå Ýîôñá ÷ñÝùóç
ãéá Ýîïäá ìåôáöïñÜò 7% åðéðñüóèåôá (äçëáäÞ, ðåñßðïõ US$9.10). Ãéá
÷þñåò åîùôåñéêïý ôá Ýîïäá ìåôáöïñÜò èá åßíáé áíáìößâïëá áêüìç
ðåñéóóüôåñá. Ôï ANSI áðáéôåß êÜèå ðáñáããåëßá íá óõíïäåýåôáé áðü Ýíá
÷áñôß ðáñáããåëßáò ôçò åôáéñåßáò. ÅíáëëáêôéêÜ, ìðïñåßôå íá óôåßëåôå Ýíá
ôóåê áìåñéêÜíéêçò ôñÜðåæáò Þ óå áìåñéêÜíéêá äïëÜñéá, ôá ïðïßá èá
ìåôñçèïýí ðñéí íá óôáëèåß ç ðáñáããåëßá óáò. (ÕðÜñ÷åé ìéá åîáßñåóç: áí
ç åôáéñåßá óáò åßíáé åíóùìáôùìÝíï ìÝëïò ôïõ ANSI, ôüôå ôï ANSI èá óáò
óôåßëåé ôá êåßìåíá êáé èá ÷ñåþóåé ôçí åôáéñåßá óáò.)
Ôï ðñüôõðï ISO åßíáé åðßóçò äéáèÝóéìï åêôüò ÁìåñéêÞò áðü åèíéêÜ ôïðéêÜ
ôìÞìáôá (ôìÞìáôá ðñïôõðïðïßçóçò áíÜ ÷þñá) ðïõ åßíáé ìÝëç åßôå ôïõ ISO
(ÄéåèíÞò Ïñãáíéóìüò Ôõðïðïßçóçò - International Organization for
Standardization) Þ ôïõ IEC (ÄéåèíÞò Çëåêôñïôå÷íéêÞ ÅðéôñïðÞ -
International Electrotechnical Commission).
Áíôßãñáöá ôçò ëßóôá ôùí åèíéêþí ôìçìÜôùí êáé ïé äéåõèýíóåéò ôïõò åßíáé
äéáèÝóéìåò áðü ôï ANSI Þ áðü Üëëá åèíéêÜ ôìÞìáôá. Åßíáé åðßóçò
äéáèÝóéìá áðü ôï ISO:
International Organization for Standardization
Central Secretariat
1, rue de Varembi
CH-1211 Genhve 20
Switzerland
Áí ðñïôéìÜôå íá ðáñáããåßëåôå ôï ðñüôõðï ìå ðéï âïëéêü êáé ãñÞãïñï
ôñüðï, èá ðñÝðåé íá ðëçñþóåôå ãéá íá Ý÷åôå áõôü ôï ðñïíüìéï. Ìðïñåßôå
íá ðáñáããåßëåôå ôï ISO/IEC 9075:1992, Information Technology -
Database Languages - SQL, áðü ôï:
Global Engineering Documents
2805 McGaw Ave
Irvine, CA 92714 (USA)
USA
ÔçëÝöùíï (áðü ïðïéáäÞðïôå ðåñéï÷Þ): +1.714.261.1455
ÔçëÝöùíï (ìüíï ãéá ÁìåñéêÞ): (800)854-7179
êáé êïóôßæåé US$308.00. Äå îÝñù áí óå áõôÞ ôçí ôéìÞ óõìðåñéëáìâÜíïíôáé
ôá Ýîïäá áðïóôïëÞò Þ ü÷é, áëëÜ õðïèÝôù üôé ç áðïóôïëÞ óôï åîùôåñéêü
(ôïõëÜ÷éóôïí) èá êïóôßæåé ðåñéóóüôåñï. Ìðïñïýí íá óáò óôåßëïõí ôï
êåßìåíï áñêåôÜ ãñÞãïñá êáé äÝ÷ïíôáé êáé ôéò "ðéï ãíùóôÝò ðéóôùôéêÝò
êÜñôåò". Ôï Global äåí Ý÷åé áêüìç ôçí ANSI Ýêäïóç ïýôå Ý÷ïõí ôéìÞ Þ
ìéá áíáìåíüìåíç çìåñïìçíßá (áí êáé ôçí ðåñéìÝíù üôé óå ìåñéêÝò
åâäïìÜäåò ìåôÜ ôç äçìïóßåõóç ôïõ ANSI êáé ìå ôéìÞ ãýñù óôá
US$300.00).
ÁãïñÜæïíôáò Ýíá áíôßãñáöï ôïõ SQL3 Working Draft
Ìðïñåßôå íá áãïñÜóåôå ìéá åêôýðùóç ôïõ SQL3 working draft áðü ôï ANSI
X3 Secretariat, CBEMA (Computer êáé Business Equipment Manufacturers
Association). ÓõíÞèùò äéáèÝôïõí ôéò "ðéï ðñüóöáôåò åêäüóåéò" ôïõ SQL3
working draft êáé ôéò ðùëïýí áðü US$60.00 ìÝ÷ñé US$65.00. Ìðïñåßôå íá
åðéêïéíùíÞóåôå ìå ôï CBEMA óôï:
CBEMA, X3 Secretariat
Attn: Lynn Barra
1250 Eye St.
Suite 200
Washington, DC 20005 (USA)
Ìðïñåßôå íá åðéêïéíùíÞóåôå ìå ôç Lynn Barra ôçëåöùíéêþò óôï
+1.202.626.5738 ãéá íá æçôÞóåôå Ýíá áíôßãñáöï, áí êáé ôï mail åßíáé
ðñïôéìüôåñï.
ÇëåêôñïíéêÞ ðñüóâáóç óôï SQL3 Working Draft
Ç ðéï ðñüóöáôç Ýêäïóç (ôç óôéãìÞ ôçò óõããñáöÞò ôïõ êåéìÝíïõ) ôïõ SQL3
(êáé ãéá ANSI êáé ISO) working draft (êáé üëá ôá ôìÞìáôÜ ôïõ) åßíáé
äéáèÝóéìç ìå "anonymous ftp" Þ ìå "ftpmail" áðü ôï:
gatekeeper.dec.com
óôï êáôÜëïãï
/pub/standards/sql/
Óå áõôüí ôïí êáôÜëïãï õðÜñ÷ïõí ðïëëÜ áñ÷åßá. ÕðÜñ÷ïõí áñ÷åßá
PostScript êáé "plain text" (ü÷é áðáñáßôçôá öïñìáñéóìÝíá, áëëÜ
äéáâÜæïíôáé óå ìéá ïèüíç ÷ùñßò éäéáßôåñï ëïãéóìéêü).
ÃåíéêÜ, ìðïñåßôå íá âñåßôå áñ÷åßá ìå ïíüìáôá üðùò:
sql-bindings-mar94.ps
sql-bindings-mar94.txt
sql-cli-mar94.ps
sql-cli-mar94.txt
sql-foundation-mar94.ps
sql-foundation-mar94.txt
sql-framework-mar94.ps
sql-framework-mar94.txt
sql-psm-mar94.ps
sql-psm-mar94.txt
Êáèþò ðáñÜãïíôáé íÝåò åêäüóåéò ôùí êåéìÝíùí, ôï "mar94" èá áëëÜæåé ãéá
íá äåßîåé ôç íÝá çìåñïìçíßá ôçò äçìïóßåõóçò (ð.÷., "aug94" åßíáé ç
áíáìåíüìåíç çìåñïìçíßá ôçò åðüìåíçò äçìïóßåõóçò ìåôÜ ôï "mar94").
Åðßóçò, ãéá ôïõò áíáãíþóôåò ðïõ äåí ìðïñïýí íá Ý÷ïõí ìéá ëßóôá ôïõ
êáôáëüãïõ ìå FTP, Ý÷ïõìå ôïðïèåôÞóåé óôïí ßäéï êáôÜëïãï Ýíá áñ÷åßï ìå
ôï üíïìá:
ls
Áõôü ôï áñ÷åßï (Ýêðëçîç!) ðåñéÝ÷åé ôç ëßóôá ôïõ êáôáëüãïõ.
Áíáêôþíôáò Áñ÷åßá êáôåõèåßáí ìå ÷ñÞóç ôïõ ftp
Áõôü åßíáé Ýíá ðáñÜäåéãìá ãéá ôï ðþò íá ÷ñçóéìïðïéåßôå ôï FTP.
ÓõãêåêñéìÝíá, äåß÷íåé ðþò íá óõíäåèåßôå óôï gatekeeper.dec.com, íá
ðÜôå óôïí êáôÜëïãï üðïõ öõëÜóóåôáé ôï âáóéêü êåßìåíï, êáé íá
ìåôáöÝñåôå ôï êåßìåíï óôï ìç÷ÜíçìÜ óáò. Óçìåéþóôå üôé ôï ìç÷ÜíçìÜ óáò
ðñÝðåé íá Ý÷åé ðñüóâáóç óôï Internet ãéá íá ôï êÜíåôå áõôü. Ôï login
åßíáé 'ftp' êáé ï êùäéêüò åßíáé ç email äéåýèõíóÞ óáò (áõôü åßíáé
ãíùóôü êáé óáí áíþíõìï ftp 'anonymous ftp'). Ç åíôïëÞ 'type binary'
÷ñçóéìïðïéåßôáé ãéá íá óéãïõñÝøåôå üôé äå èá ÷Üóåôå êÜðïéá bits áðü
ôï(á) áñ÷åßï(á) ðïõ èá ëÜâåôå. H 'get' êáôåâÜæåé Ýíá áñ÷åßï ôç öïñÜ.
Ôá ó÷üëéá óôï ðáñáêÜôù script åßíáé ìÝóá óå angle brackets < óáí áõôÜ
> .
% ftp gatekeeper.dec.com
Connected to gatekeeper.dec.com.
220- *** /etc/motd.ftp ***
Gatekeeper.DEC.COM is an unsupported service of DEC Corporate Research.
<...this goes on for a while...>
220 gatekeeper.dec.com FTP server (Ýêäïóç 5.83 Sat ... 1992) ready.
Name (gatekeeper.dec.com:<yourlogin here>): ftp <anonymous also works>
331 Guest login ok, send ident as password.
Password: <enter your email address here >
230 Guest login ok, access restrictions apply.
Remote system type is UNIX. <or whatever>
Using binary mode to transfer files.
ftp> cd pub/standards/sql
250 CWD command successful.
ftp> dir
200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.
total 9529
-r--r--r-- 1 root system 357782 Feb 25 10:18 x3h2-93-081.ps
-r--r--r-- 1 root system 158782 Feb 25 10:19 x3h2-93-081.txt
-r--r--r-- 1 root system 195202 Feb 25 10:20 x3h2-93-082.ps
-r--r--r-- 1 root system 90900 Feb 25 10:20 x3h2-93-082.txt
-r--r--r-- 1 root system 5856284 Feb 25 09:55 x3h2-93-091.ps
-r--r--r-- 1 root system 3043687 Feb 25 09:57 x3h2-93-091.txt
226 Transfer complete.
ftp> type binary
200 Type set to I.
ftp> get x3h2-93-082.txt
200 PORT command successful.
150 Opening BINARY mode data connection for x3h2-93-082.txt (90900 bytes).
226 Transfer complete.
90900 bytes received in 0.53 seconds (166.11 Kbytes/s)
ftp> quit
% <ôï áñ÷åßï åßíáé ôþñá óôïí êáôÜëïãü óáò óáí x3h2-93-082.txt>
Áíáêôþíôáò Áñ÷åßá ÷ùñßò áðåõèåßáò õðïóôÞñéîç ftp
Ç Digital Equipment Corporation, üðùò êáé ðïëëÝò Üëëåò åôáéñåßåò,
ðáñÝ÷åé õðçñåóßá ftp email. Ç áðÜíôçóç ìðïñåß íá ÷ñåéáóôåß ãéá íá
öôÜóåé áñêåôÝò ìÝñåò, áëëÜ ðáñÝ÷åé ìéá õðçñåóßá éóïäýíáìç ìå ôï ftp
ãéá áõôïýò ðïõ äåí Ý÷ïõí áðåõèåßáò ftp ðñüóâáóç óôï Internet. Ç
äéåýèõíóç ôïõ server åßíáé:
ftpmail@decwrl.dec.com
Ôï ðáñáêÜôù script èá áíáêôÞóåé ôï PostScript áñ÷åßï ôçò ôåëåõôáßáò
Ýêäïóçò ôïõ SQL3 êåéìÝíïõ:
reply joe.programmer@imaginary-corp.com
connect gatekeeper.dec.com anonymous
binary
compress
Ôï ðáñáêÜôù script èá áíáêôÞóåé ôï PostScript áñ÷åßï ôçò ôåëåõôáßáò
Ýêäïóçò ôïõ SQL3 êåéìÝíïõ:
reply joe.programmer@imaginary-corp.com
connect gatekeeper.dec.com anonymous
binary
compress
uuencode
chdir /pub/standards/sql
get x3h2-93-091.ps
quit
Ç ðñþôç ãñáììÞ áðü ôéò åíôïëÝò ôïõ script æçôÜ áðü ôï äéáêïìéóôÞ
(server) íá óáò åðéóôñÝøåé ôá æçôïýìåíá áñ÷åßá. Èá ðñÝðåé íá
áíôéêáôáóôÞóåôå ôï "joe.programmer@imaginary-corp.com" ìå ôçí
äéåýèõíóÞ óáò óôï Internet. Ôï áñ÷åßï óå áõôü ôï ðáñÜäåéãìá,
x3h2-93-091.ps, åðéóôñÝöåôáé óå ìïñöÞ "compress"ed "uuencode"d óáí 34
äéáöïñåôéêÜ ìçíýìáôá email. Áí ôï ðåñéâÜëëïí óáò äåí ðáñÝ÷åé åñãáëåßá
ãéá åðáíáêáôáóêåõÞ ôÝôïéùí áñ÷åßùí, ôüôå ìðïñåßôå íá áíáêôÞóåôå ôï
áñ÷åßï óáí plain text ìå ôï áêüëïõèï script:
reply joe.programmer@imaginary-corp.com
connect gatekeeper.dec.com anonymous
chdir /pub/standards/sql
get x3h2-93-091.ps
quit
ÁëëÜ óáò ðñïåéäïðïéïýìå, ôï áñ÷åßï .ps ðïëý ðéèáíÜ èá óôáëèåß óå
ðåñéóóüôåñá áðü 70 ôìÞìáôá!
Ãéá íá áíáêôÞóåôå ïðïéïäÞðïôå Üëëï óõãêåêñéìÝíï áñ÷åßï, åêôüò ôïõ
x3h2-93-091.ps, áðëÜ áíôéêáôáóôÞóôå ôï "x3h2-93-091.ps" ìå ôï üíïìá
ôïõ áñ÷åßïõ ðïõ åðéèõìåßôå. Ãéá íá ðÜñåôå ôç ëßóôá üëùí ôùí
äéáèÝóéìùí áñ÷åßùí ôïõ êáôáëüãïõ, áíôéêáôáóôÞóôå ôï "get
x3h2-93-091.ps" ìå ôï "dir".
[1m23.10. ÔìÞìá 1 - ÔñÝ÷ïõóá êáôÜóôáóç ôïõ ISO/ANSI SQL[0m
Áõôü ôï êåöÜëáéï åßíáé ìéá ðçãÞ ðëçñïöïñßáò ó÷åôéêÜ ìå ôçí ðñüôõðç
äéåñãáóßá SQL êáé ôçí ôñÝ÷ïõóá êáôÜóôáóÞ ôçò.
ÔñÝ÷ïõóá êáôÜóôáóç:
Ç áíÜðôõîÞ ôïõ åßíáé õðü åîÝëéîç ãéá íá åðåêôåßíåé ôçí SQL óå ìéá
ïëïêëçñùìÝíç õðïëïãéóôéêÜ ãëþóóá ãéá ôïí êáèïñéóìü êáé äéá÷åßñéóç
persistent, óýíèåôùí áíôéêåéìÝíùí. Áõôü ðåñéëáìâÜíåé : generalization
êáé specialization hierarchies, ðïëëáðëÞ êëçñïíïìéêüôçôá, ôýðïõò
äåäïìÝíùí êáèïñéóìÝíùí áðü ôïí ÷ñÞóôç, triggers êáé assertions,
õðïóôÞñéîç ãéá Ýìðåéñá óõóôÞìáôá, áíáäñïìéêÝò åñùôÞóåéò, êáé åðéðëÝïí
åñãáëåßá äéá÷åßñéóçò äåäïìÝíùí. ÐåñéëáìâÜíåé åðßóçò ôéò ðñïäéáãñáöÝò
ôùí áöçñçìÝíùí ôýðùí äåäïìÝíùí (abstract data types -ADTs), object
identifiers, ìåèüäïõò, êëçñïíïìéêüôçôá, ðïëõìïñöéóìü, encapsulation,
êáé üëåò ôéò åõêïëßåò ðïõ ó÷åôßæïíôáé ìå ôç äéá÷åßñéóç äåäïìÝíùí ôùí
áíôéêåéìÝíùí.
Ôï öèéíüðùñï ôïõ 1996, áñêåôÜ ôìÞìáôá ôïõ SQL3 ðÝñáóáí áðü øçöïöïñßá
ISO CD. ÁõôÜ Þôáí ôá SQL/Framework, SQL/Foundation, êáé SQL/Bindings.
ÁõôÞ ç øçöïöïñßá áðÝôõ÷å (üðùò Þôáí áíáìåíüìåíï) ìå 900 Þ ðåñßðïõ ôüóá
ó÷üëéá. Óôá ôÝëç Éáíïõáñßïõ, Ýãéíå êÜðïéá óõíÜíôçóç óýíôáîçò ôïõ ISO
DBL êáôÜ ôçí ïðïßá åðåîåñãÜóôçêáí ëýóåéò ãéá Ýíá ìåãÜëï áñéèìü
ðñïâëçìÜôùí ôá ïðïßá åßôå åíóùìáôþèçêáí ìå ó÷üëéá ìÝóù øçöïöïñßáò åßôå
óôÜëèçêáí óáí îå÷ùñéóôÜ papers. Ìéá êáé ç óõíÜíôçóç óýíôáîçò ôïõ DBL
äåí ìðüñåóå íá åðåîåñãáóôåß üëá ôá ó÷üëéá, ç óõíÜíôçóç óýíôáîçò
ðáñáôÜèçêå. Ç ïëïêëÞñùóç ôçò óõíÜíôçóçò óýíôáîçò ðñïãñáììáôßóôçêå ãéá
ôá ôÝëç Éïõëßïõ, 1997, óôï Ëïíäßíï.
ÌåôÜ ôç óõíÜíôçóç óýíôáîçò ôïõ Éïõëßïõ, áíáìÝíåôáé íá æçôçèåß ìéá
ôåëéêÞ øçöïöïñßá ãéá üëá áõôÜ ôá ôìÞìáôá ôçò SQL. Ç äéáäéêáóßá ãéá ôçí
ôåëéêÞ øçöïöïñßá èá êñáôÞóåé 6 ðåñßðïõ ìÞíåò êáé èá ãßíåé ìéá
óõíÜíôçóç óýíôáîçò DBL, ìåôÜ ôçí ïðïßá èá ãßíåé ìéá øçöïöïñßá DIS êáé
ìéá ó÷åôéêÜ ãñÞãïñç øçöïöïñßá IS .
Ïé äéáäéêáóßåò ISO Ý÷ïõí áëëÜîåé áðü ôï SQL/92, Ýôóé ïé åðéôñïðÝò ãéá
ôçí SQL äïõëåýïõí áêüìç ãéá ôïí êáèïñéóìü ôùí áêñéâþí ëåðôïìåñåéþí ôçò
äéáäéêáóßáò.
Áí ðÜíå üëá êáëÜ, áõôÜ ôá ôìÞìáôá ôçò SQL3 èá ãßíïõí Ýíá åðßóçìï
ðñüôõðï ISO/IEC óôá ôÝëç ôïõ 1998, áëëÜ ôï ðñüãñáììá åßíáé ðïëý
óöé÷ôü.
Ôï 1993, ïé åðéôñïðÝò áíÜðôõîçò ANSI êáé ISO áðïöÜóéóáí íá ÷ùñßóïõí ôç
ìåëëïíôéêÞ áíÜðôõîç ôçò SQL óå Ýíá ðïëõìåñÝò ðñüôõðï. Ôá ôìÞìáôá áõôÜ
åßíáé:
· ÔìÞìá 1: Framework Ìéá ìç ôå÷íéêÞ ðåñéãñáöÞ ãéá ôï ðþò åßíáé
äïìçìÝíï ôï êåßìåíï.
· ÔìÞìá 2: Foundation Ïé ðñïäéáãñáöÝò ôïõ óõóôÞìáôïò,
óõìðåñéëáìâáíïìÝíïõ üëùí ôùí íÝùí ÷áñáêôçñéóôéêþí ADT.
· ÔìÞìá 3: SQL/CLI Ôï Call Level Interface.
· ÔìÞìá 4: SQL/PSM Ïé ðñïäéáãñáöÝò ôùí stored procedures,
óõìðåñéëáìâáíïìÝíùí õðïëïãéóôéêþí óõìðëçñþóåùí.
· ÔìÞìá 5: SQL/Bindings Ôá Dynamic SQL êáé Embedded SQL bindings ðïõ
ðÜñèçêáí áðü ôï SQL-92.
· ÔìÞìá 6: SQL/XA Ïé ðñïäéáãñáöÝò SQL ôïõ äçìïöéëïýò XA Interface ðïõ
áíáðôýóóåôáé áðü ôçí X/Open
· ÔìÞìá 7:SQL/Temporal ÐñïóèÝôåé óôá ðñüôõðá SQL éêáíüôçôåò ó÷åôéêÝò
ìå ôï ÷ñüíï.
Óôçí ÁìåñéêÞ, ïëüêëçñç ç SQL3 åðåîåñãÜæåôáé êáé óáí ANSI Domestic
("D") project êáé óáí ISO project. Ôï áíáìåíüìåíï ÷ñïíéêü ðáñÜèõñï ãéá
ôçí ïëïêëÞñùóç ôçò SQL3 åßíáé ôï 1999.
Ôá SQL/CLI êáé SQL/PSM åðåîåñãÜæïíôáé üóï ãñçãïñüôåñá ãßíåôáé óáí
addendums óôçí SQL-92. Óôçí ÁìåñéêÞ, áõôÜ åðåîåñãÜæïíôáé ìüíï óáí
ÄéåèíÞ ¸ñãá (International - "I"). Ç SQL/CLI ïëïêëçñþèçêå ôï 1995. Ç
SQL/PSM ðñÝðåé íá Ý÷åé ïëïêëçñùèåß óôá ôÝëç ôïõ 1996.
Åðéðñüóèåôá ôçò SQL3 åñãáóßáò, Ýíáò áñéèìüò åðéðëÝïí Ýñãùí are
persued:
· SQL/MM Ìéá ðñïóðÜèåéá íá ïñéóôïýí ðñüôõðá ðáêÝôá ðïëõìÝóùí
÷ñçóéìïðïéþíôáò ôéò äõíáôüôçôåò ôçò SQL3 ADT.
· Ðñüóâáóç óå áðïìáêñõóìÝíá äåäïìÝíá - Remote Data Access (RDA)
ÅðéôñïðÝò Ðñïôýðùí êáé Äéáäéêáóéþí ÕðÜñ÷åé ðñáãìáôéêÜ ìåãÜëïò áñéèìüò
åðéôñïðþí ðñïôýðùí SQL óå üëï ôïí êüóìï. ÕðÜñ÷åé Ýíá äéåèíÝò ãêñïõð
ôïõ ðñïôýðïõ SQL óáí ôìÞìá ôïõ ISO. ÐïëëÝò ÷þñåò Ý÷ïõí åðéôñïðÝò ðïõ
áó÷ïëïýíôáé ìå ôçí SQL. ÁõôÝò ïé ÷þñåò (óõíÞèùò) óôÝëíïõí
áíôéðñïóþðïõò óôéò óõíáíôÞóåéò ISO/IEC JTC1/SC 21/WG3 DBL. Ïé ÷þñåò
ðïõ óõììåôÝ÷ïõí åíåñãÜ óôç äéáäéêáóßá ôïõ ðñïôýðïõ ISO SQL åßíáé ïé:
· Áõóôñáëßá
· Âñáæéëßá
· ÊáíáäÜò
· Ãáëëßá
· Ãåñìáíßá
· Éáðùíßá
· ÊïñÝá
· Ïëëáíäßá
· Áããëßá
· ÁìåñéêÞ
NIST Íïìéìïðïßçóç
Ïé õëïðïéÞóåéò ôçò SQL íïìéìïðïéïýíôáé (óôçí ÁìåñéêÞ) áðü ôï Åèíéêü
Éíóôéôïýôï Ðñïôýðùí êáé ÅëÝã÷ïõ (NIST). Ôï NIST Ý÷åé ãéá ôçí þñá Ýíá
óýíïëï áðü ôåóô íïìéìüôçôáò ãéá ôï entry level SQL-92. Ïé áêñéâåßò
ðëçñïöïñßåò ãéá ôéò áðáéôÞóåéò ôçò NIST íïìéìïðïßçóçò êáèïñßæïíôáé ùò
Ïìïóðïíäéáêü Ðñüôõðï Åðåîåñãáóßáò Ðëçñïöïñßáò - Federal Information
Processing Standard (FIPS). Ïé ôñÝ÷ïõóåò áðáéôÞóåéò ãéá ôçí SQL
ïñßæïíôáé óôï FIPS 127-2. Ìðïñåßôå íá ðÜñåôå ôéò ôñÝ÷ïõóåò Postscript
êáé Text åêäüóåéò áõôïý ôïõ êåéìÝíïõ áðü ôï NIST. Ç ëßóôá ôùí
ôñå÷üíôùí íïìéìïðïéçìÝíùí SQL ðñïúüíôùí ìðïñåß åðßóçò íá âñåèåß óôï
NIST.
Åêäüóåéò êáé ¶ñèñá ó÷åôéêÜ ìå ôï ðñüôõðï ôçò SQL
ÕðÜñ÷ïõí äýï åêäüóåéò ó÷åôéêÜ ìå ôï ðñüôõðï SQL. Êáé ïé äýï
äéáôßèåíôáé áðü ôï ANSI:
· ISO/IEC 9075:1992, "Information Technology --- Database Languages
--- SQL"
· ANSI X3.135-1992, "Database Language SQL"
Ïé äõï åêäüóåéò ôïõ ðñïôýðïõ SQL åßíáé ïëüéäéåò åêôüò áðü ôï åîþöõëëï
êáé ôéò áíáöïñÝò óå Üëëá ðñüôõðá. Êáé ïé äýï äéáôßèåíôáé áðü ôï :
American National Standards Institute
1430 Broadway
New York, NY 10018
USA
Phone (sales): +1.212.642.4900
Åðéðñüóèåôá óôï ðñüôõðï SQL-92, õðÜñ÷åé Ýíá Technical Corrigendum
(äéïñèþóåéò bug):
* Technical Corrigendum 1:1994 to ISO/IEC 9075:1992
Ôï TC 1 ðñÝðåé íá äéáôßèåôáé åðßóçò áðü ôï ANSI. ÕðÜñ÷åé ìüíï ç ISO
Ýêäïóç ôïõ TC 1 -- åöáñìüæåôáé êáé óôçí ISO êáé ANSI Ýêäïóç ôïõ
SQL-92.
Åðéðñüóèåôá, Ý÷ïõí ãñáöôåß áñêåôÜ âéâëßá ó÷åôéêÜ ìå ôï ðñüôõðï 1992
SQL. ÁõôÜ ôá âéâëßá ðáñÝ÷ïõí ìéá êáëýôåñá áíáãíþóéìç ðåñéãñáöÞ ôïõ
ðñïôýðïõ áðü üôé ôï ßäéï ôï ðñüôõðï.
Ó÷åôéæüìåíá ðñüôõðá
Åíáò óýíïëï ðñïôýðùí åíäéáöÝñïõí ôçí SQL êïéíüôçôá. Áõôü ôï ôìÞìá
ðåñéÝ÷åé äåßêôåò óå ðëçñïöïñßåò ãéá áõôÝò ôéò ðñïóðÜèåéåò. Áõôïß ïé
äåßêôåò èá áõîçèïýí êáèþò Ýîôñá ðëçñïöïñßåò äéáôßèåíôáé óôï web.
· ÐåñéâÜëëïíôá SQL (FIPS 193)
· Repository ÓõóôÞìáôá Åðüìåíçò ÃåíéÜò (X3H4) - ìéá News Release ðïõ
æçôÜ óõììåôï÷Þ óôï "Áíáðôýóóïíôáò Ðñüôõðá ãéá Repository ÓõóôÞìáôá
Åðüìåíçò ÃåíéÜò."
[1m23.11. ÔìÞìá 2 - ISO/ANSI SQL Foundation[0m
¸íá óçìáíôéêü ôìÞìá ôçò SQL3 ðñïóðÜèåéáò âñßóêåôáé óôï êåßìåíï SQL
Foundation :
· ÂáóéêÝò äõíáôüôçôåò SQL/PSM (moved form SQL/PSM-92)
· ÍÝïé ôýðïé äåäïìÝíùí
· Triggers
· Õðïðßíáêåò
· ÁöçñçìÝíïé Ôýðïé ÄåäïìÝíùí - Abstract Data Types (ADT)
· Áíôéêåéìåíïóôñáöåßò Äõíáôüôçôåò
ÕðÜñ÷ïõí áñêåôÜ ðñïáðáéôïýìåíá óôéò áíôéêåéìåíïóôñáöåßò äõíáôüôçôåò:
· Éêáíüôçôá íá ïñßæåôå óýíèåôåò ëåéôïõñãßåò
· ÁðïèÞêåõóç óýíèåôùí ëåéôïõñãéþí óôç âÜóç
· ÊëÞóç åîùôåñéêþí äéáäéêáóéþí ÌåñéêÝò ëåéôïõñãßåò ìðïñåß íá ìçí
åßíáé óå SQL, Þ ìðïñåß íá áðáéôïýí åîùôåñéêÝò ðáñåìâÜóåéò
ÁõôÝò ïé äõíáôüôçôåò ïñßæïíôáé óáí ôìÞìá ôïõ SQL/PSM
Ãßíåôáé ìéá óçìáíôéêÞ åñãáóßá ãéá íá åêêáèáñéóôåß ôï ìïíôÝëï
áíôéêåéìÝíïõ SQL-3 êáé íá åõèõãñáììéóôåß ìå ôï ìïíôÝëï áíôéêåéìÝíïõ
ðïõ ðñïôÜèçêå áðü ôï ODMG. ÁõôÞ ç ðñïóðÜèåéá ðåñéãñÜöåôáé óôï X3H2 êáé
ISO DBL paper: Accomodating SQL3 and ODMG. Åßíáé åðßóçò äéáèÝóéìç ìéá
ðñüóöáôç Ýêäïóç óôï SQL3/OQL Merger.
SQL3 Timing
Ç åñãáóßá ðÜíù óôï SQL3 âñßóêåôáé óå åîÝëéîç, áëëÜ ôá ôåëéêÜ ðñüôõðá
èá ÷ñåéáóôïýí ÷ñüíéá áêüìç ãéá íá ïëïêëçñùèïýí.
· ÄéåèíÞò øçöïöïñßá ãéá ôçí ðñüïäï ôïõ SQL3 Foundation áðü ôï
Ðñü÷åéñï ¸íôõðï Åñãáóßáò ùò ôï Ðñü÷åéñï ¸íôõðï ÅðéôñïðÞò (Committee
Draft - CD) Ýëáâå ÷þñá ôï öèéíüðùñï ôïõ 1996.
· Ç øçöïöïñßá áíáìÝíåôáé íá ðñïêáëÝóåé ðïëëÜ ó÷üëéá
· Åßíáé ðéèáíü íá æçôçèåß ìéá äåýôåñç øçöïöïñßá CD
· Ìéá Draft Øçöïöïñßá Äéåèíþí Ðñïôýðùí åßíáé ðéèáíü íá ãßíåé óôá ìÝóá
ôïõ 1998
· Ôï ÄéåèíÝò Ðñüôõðï ìðïñåß íá ïëïêëçñùèåß óôá ìÝóá ôïõ 1999.
Ç ANSI Ýêäïóç ôïõ ðñïôýðïõ Ý÷åé ðáñüìïéï ÷ñïíïäéÜãñáììá.
[1m23.12. ÔìÞìá 3 - ISO/ANSI SQL Call Level Interface[0m
Ôï SQL/CLI åßíáé Ýíá ðñïãñáììáôéóôéêü interface åðéðÝäïõ êëÞóåùí ãéá
SQL âÜóåéò. ¸÷åé ó÷åäéáóôåß ãéá íá õðïóôçñßæåé ðñüóâáóç óå âÜóåéò áðü
shrink-wrapped åöáñìïãÝò. Ôï CLI äçìéïõñãÞèçêå áñ÷éêÜ áðü ìéá
õðïåðéôñïðÞ ôïõ SQL Access Group (SAG). Ïé ðñïäéáãñáöÝò ôïõ SAG/CLI
åêäüèçêáí óáí ôéò ðñïäéáãñáöÝò ôïõ Microsoft Open DataBase
Connectivity (ODBC) ôï 1992. Ôï 1993, ôï SAG Ýóôåéëå ôï CLI óôéò
åðéôñïðÝò ANSI êáé ISO SQL. (Ôï ãêñïõð SQL Access Ý÷åé óõã÷ùíåõèåß
ôþñá ìå ôï X/Open consortium.)
Ôï SQL/CLI ðáñÝ÷åé Ýíá äéåèíÝò ðñüôõðï ãéá :
· CLI áíåîÜñôçôï õëïðïßçóçò, ãéá ðñüóâáóç óå âÜóåéò SQL
· Client-Server åñãáëåßá ðïõ ìðïñïýí íá Ý÷ïõí ðñüóâáóç óå ìéá âÜóç
ìÝóù äõíáìéêþí âéâëéïèçêþí
· ÕðïóôÞñéîç êáé åíèÜññõíóç ðëïýóéïõ óõíüëïõ åñãáëåßùí Client-server
SQL/CLI Timing
Óôá ðëáßóéá ôçò äéáäéêáóßá ôõðïðïßçóçò, ôï SQL/CLI åðåîåñãÜæåôáé ìå
ìåãÜëç ðñïôåñáéüôçôá.
· Ôï SQL/CLI åßíáé Ýíá óõìðëÞñùìá ôïõ ðñïôýðïõ 1992 SQL (SQL-92)
· Ïëïêëçñþèçêå óáí ðñüôõðï ISO ôï 1995
· ISO/IEC 9075-3:1995 Information technology -- Database languages --
SQL -- Part 3: Call-Level Interface (SQL/CLI)
· Ç ôñÝ÷ïõóá SQL/CLI ðñïóðÜèåéá ðïõ ãßíåôáé åßíáé íá ðñïóôåèåß
õðïóôÞñéîç ãéá ÷áñáêôçñéóôéêÜ ôçò SQL3
[1m23.13. ÔìÞìá 4 - ISO/ANSI SQL Persistent Stored Modules[0m
Ôï SQL/PSM åðåêôåßíåé ôçí SQL ðñïóèÝôïíôáò:
· ÄçëùôéêÝò/ÄéáäéêáóôéêÝò åðåêôÜóåéò
· Multi-statement êáé Stored Procedures
· ÅîùôåñéêÝò óõíáñôÞóåéò êáé êëÞóåéò äéáäéêáóéþí
Åêôüò ôïõ üôé åßíáé Ýíá áîéüëïãï åñãáëåßï áíÜðôõîçò åöáñìïãþí, ôï
SQL/PSM ðáñÝ÷åé ôç èåìåëéþäç õðïóôÞñéîç ãéá áíôéêåéìåíïóôñáöåßò
äõíáôüôçôåò óôçí SQL3.
Multi-statement êáé Stored Procedures
Ïé Multi-statement êáé stored procedures ðñïóöÝñïõí ìéá ðïéêéëßá
ðëåïíåêôçìÜôùí óå Ýíá ðåñéâÜëëïí client/server:
· Áðüäïóç- Ìéá êáé ìéá stored procedure ìðïñåß íá åêôåëÝóåé ðïëëáðëÝò
SQL åíôïëÝò, ìåéþíåôáé ç áëëçëåðßäñáóç ìå ôïí ðåëÜôç (client).
· ÁóöÜëåéá - Åíáò ÷ñÞóôçò ìðïñåß íá áðïêôÞóåé ôï äéêáßùìá íá êáëåß
ìéá stored procedure ðïõ åíçìåñþíåé Ýíá ðßíáêá Þ Ýíá óýíïëï ðéíÜêùí
áëëÜ ìçí Ý÷åé ôï äéêáßùìá ôçò áðåõèåßáò åíçìÝñùóçò ôùí ðéíÜêùí
· Åðáíá÷ñçóéìïðïéÞóéìïò êþäéêáò - Ï êþäéêáò óå ìéá stored procedure
äå ÷ñåéÜæåôáé íá îáíáãñáöôåß êáé íá îáíáåëåã÷èåß ãéá êÜèå client
åñãáëåßï ðïõ Ý÷åé ðñüóâáóç óôç âÜóç.
· ¸ëåã÷ïò - ÐáñÝ÷åé Ýíá ìüíï óçìåßï ïñéóìïý êáé åëÝã÷ïõ ôçò ëïãéêÞò
ôçò åöáñìïãÞò.
ÄçëùôéêÝò/ÄéáäéêáóôéêÝò åðåêôÜóåéò
Ç ÄéáäéêáóôéêÞ Ãëþóóá ðñïóèÝôåé ôçí éó÷ý ìéáò ðáñáäïóéáêÞò ãëþóóáò
ðñïãñáììáôéóìïý óôçí SQL ìÝóù åíôïëþí åëÝã÷ïõ ñïÞò êáé ìéá ðïéêéëßá
Üëëùí ðñïãñáììáôéóôéêþí êáôáóêåõþí.
ÅíôïëÝò ÅëÝã÷ïõ ñïÞò
· If-then-else
· Looping constructs
· Exception handling
· Case statement
· Begin-End blocks
Ïé äéáäéêáóôéêÝò åðåêôÜóåéò ðåñéëáìâÜíïõí êáé Üëëåò ðñïãñáììáôéóôéêÝò
êáôáóêåõÝò:
· Äçëþóåéò ìåôáâëçôþí
· ÅíôïëÝò Set ãéá áíÜèåóç ôéìþí
· ËÞøç äéáãíùóôéêþí ãéá ôéò äéåñãáóßåò êáé ðëçñïöïñßåò êáôÜóôáóçò
ÅðéðëÝïí, üëåò ïé ðáñáäïóéáêÝò SQL åíôïëÝò ìðïñïýí íá óõìðåñéëçöèïýí
óå äéáäéêáóßåò multi-statement.
ÊëÞóåéò Åîùôåñéêþí Äéáäéêáóéþí êáé ÓõíáñôÞóåùí ¸íá ÷áñáêôçñéóôéêü ðïõ
áíáöÝñåôáé óõ÷íÜ óôéò åõ÷åôÞñéåò ëßóôåò ôïõ ôé èá åðéèõìïýóáìå ãéá
ðïëëÜ ðñïúüíôá âÜóåùí, êáé ðïõ Ý÷åé õëïðïéçèåß óå ìåñéêÝò, åßíáé ç
äõíáôüôçôá íá åìðëïõôéóìïý ôùí åíóùìáôùìÝíùí ÷áñáêôçñéóôéêþí ìå
êëÞóåéò óå äéáäéêáóßåò ðïõ Ý÷åé ãñÜøåé ï ÷ñÞóôçò åîùôåñéêÜ åêôüò ôçò
âÜóçò.
· ÅðéôñÝðåé óå Ýíá óõãêåêñéìÝíï site Þ åöáñìïãÞ íá ðñïóèÝóåé ôéò
äéêÝò ôïõ óõíáñôÞóåéò ãéá ôç âÜóç
· Ìðïñåß íá ÷ñçóéìïðïéçèåß áðü ôéò åöáñìïãÝò âÜóåéò äåäïìÝíùí
Ôï ðëåïíÝêôçìá áõôÞò ôçò äõíáôüôçôáò åßíáé üôé äßíåé óôç âÜóç (óõíåðþò
êáé óôéò åöáñìïãÝò âÜóåùí) ðñüóâáóç óå ôåñÜóôéï áñéèìü äéáäéêáóéþí êáé
óõíáñôÞóåùí.
×ñïíéóìüò ôïõ SQL/PSM
Ôï SQL/PSM Ý÷åé åí óõíôïìßá:
· Ôï SQL/PSM åßíáé ìéá ðñïóèÞêç óôï SQL-92
· ÄéåèíÞò øçöïöïñßá ãéá ôçí ðñüïäï ôïõ SQL/PSM áðü ôï Draft ÄéåèíÝò
Ðñüôõðï óôï ÄéåèíÝò Ðñüôõðï ïëïêëçñþèçêå ôïí ÉáíïõÜñéï ôïõ 1996.
· Ç äéïñèùôéêÞ óõíåäñßáóç ôï ÌÜéï ôïõ 1996 äåí åðÝëõóå üëá ôá ó÷üëéá
· Ç óõíÝ÷éóç ôçò äéïñèùôéêÞò óõíåäñßáóçò PSM ðñïãñáììáôßóôçêå áðü ôéò
30 Óåðôåìâñßïõ ìÝ÷ñé ôéò 4 Ïêôùâñßïõ ôïõ 1996
· Ôï ÷ñïíïäéÜãñáììá åßíáé ðéåóôéêü áëëÜ õðÜñ÷åé ìéá ðéèáíüôçôá íá
åêäïèåß ôï PSM ìÝóá óôï 1996.
· Ï åðßóçìïò ðñïóäéïñéóìüò èá åßíáé: ISO/IEC DIS 9075-4:199?
Information technology -- Database languages -- SQL -- Part 4: SQL
Persistent Stored Modules (SQL/PSM)
· ¸÷åé Þäç îåêéíÞóåé äïõëåéÜ ãéá ôçí ðñïóèÞêç õðïóôÞñéîçò SQL/PSM óôá
÷áñáêôçñéóôéêÜ ôçò SQL3.
[1m23.14. ÔìÞìá 5 - ÔõðïðïéÞóåéò - Äåóìåýóåéò ISO/ANSI SQL/ ISO/ANSI[0m
[1mSQL/Bindings[0m
Ãéá åõêïëßá áíáöïñþí, ïé äåóìåýóåéò, ôõðïðïéÞóåéò ôçò ãëþóóáò
ðñïãñáììáôéóìïý Ý÷ïõí óõãêåíôñùèåß óå Ýíá îå÷ùñéóôü êåßìåíï. Ç
ôñÝ÷ïõóá Ýêäïóç åßíáé áðëÜ Ýíá áðüóðáóìá áðü ôá ðñüôõðá ôçò
SQL-92(äõíáìéêÜ (dynamic) êáé åíóùìáôïýìåíá (embedded)).
ÐáñáìÝíåé áäéåõêñßíéóôç ìéá ðïéêéëßá èåìÜôùí ôõðïðïßçóçò ôçò ãëþóóáò.
Óôçí ðáñáäïóéáêÞ ðñïãñáììáôéóôéêÞ ãëþóóá, õðÜñ÷ïõí ïé áðåéêïíßóåéò ôùí
ôýðùí äåäïìÝíùí ôçò SQL-92. Ðáñüëá áõôÜ, èá ðñÝðåé íá ïñéóôïýí êáé ïé
áðåéêïíßóåéò ìåôáîý ôùí áíôéêåéìÝíùí ôçò SQL êáé ôùí ìåôáâëçôþí ôçò
ðñïãñáììáôéóôéêÞò ãëþóóáò..
Ãéá ôéò áíôéêåéìåíïóôñáöåßò ãëþóóåò, ðñÝðåé íá ïñéóôåß ç áðåéêüíéóç
ãéá ôïõò ôýðïõò äåäïìÝíùí ôçò SQL êáé ìåôáîý ôïõ ìïíôÝëïõ áíôéêåéìÝíùí
ôçò SQL êáé ôïõ ìïíôÝëïõ áíôéêåéìÝíùí ôçò áíôéêåéìåíïóôñáöïýò ãëþóóáò.
Ôï ìïíôÝëï äåäïìÝíùí èá ðñÝðåé íá ïñéóôéêïðïéçèåß ðñéí áñ÷ßóåé íá
ãßíåôáé áíáöïñÜ óå ôÝôïéïõ ôýðïõ ðñïâëÞìáôá.
Ïé ôõðïðïéÞóåéò ôçò ãëþóóáò èá ïëïêëçñùèïýí ùò ìÝñïõò ôïõ ðñüôõðïõ
SQL3.
[1m23.15. ÔìÞìá 6 - ISO/ANSI SQL XA Interface Specialization (SQL/XA)[0m
Ïé ðñïäéáãñáöÝò áõôÝò èá ôõðïðïéÞóïõí Ýíá ðñïãñáììáôéóôéêü interface
(API) ìåôáîý åíüò ãåíéêïý Äéá÷åéñéóôÞ Óõíäéáëëáãþí (Transaction
Manager) êáé åíüò Äéá÷åéñéóôÞ Ðüñùí (Resource Manager) SQL. Èá
ôõðïðïéÞóåé ôéò êëÞóåéò óõíáñôÞóåùí, âáóéæüìåíïò óôá ðñüôõðá ôïõ
ISO/IEC 10026, "Distributed Transaction Processing", ðïõ Ýíáò
Äéá÷åéñéóôÞò Ðüñùí SQL èá ðñÝðåé íá õðïóôçñßæåé, ãéá íá êÜíåé commit
äýï óôáäßùí (two-phase commit) Ôï âáóéêü êåßìåíï áíáöïñÜò åîÜãåôáé áðü
ìéá äçìïóßåõóç ôïõ X/Open, ìå ôçí Üäåéá ôïõ X/Open, ðïõ ðñïóäéïñßæåé
ñçôÜ ôéò ðáñáìÝôñïõò åéóüäïõ êáé åîüäïõ êáé ôçí óçìåéïãñáößá
(semantics), ãéá ôéò áêüëïõèåò óõíáñôÞóåéò: xa_close, xa_commit,
xa_complete, xa_end, xa_forget,xa_open, xa_prepare, xa_recover,
xa_rollback, êáé xa_start.
Ï ISO åðé÷åéñåß íá åðéôá÷ýíåé ôéò ðñïäéáãñáöÝò ôïõ X/Open XA. Ç
äéáäéêáóßá åðéôÜ÷õíóçò õéïèåôåß âéïìç÷áíéêÝò ðñïäéáãñáöÝò ÷ùñßò
áëëáãÝò. Ç øçöïöïñßá ãéá ôï XA óôï ISO SC21, JTC åðßðåäï 1, Üñ÷éóå
óôéò 27 Áðñéëßïõ, 1995 êáé ôåëåßùóå óôéò 27 Ïêôùâñßïõ, 1995. Áí ôï 75
ôùí øçöïöüñùí åãêñßíïõí ôéò ðñïäéáãñáöÝò ôïõ XA, êáé áðü ôá 2/3 ôùí
p-ìåëþí ôïõ JTC 1, èá áðïôåëÝóåé Ýíá ÄéåèíÝò Ðñüôõðï. Áí ç øçöïöïñßá
ôï åãêñßíåé, ôï SQL/XA èá ìðïñïýóå íá ãßíåé Ýíá ðñüôõðï ìÝóá óôï 1996.
[1m23.16. Part 7 - ISO/ANSI SQL Temporal[0m
Ç Temporal SQL áó÷ïëåßôáé ìå ÷ñïíéêÜ åîáñôþìåíá äåäïìÝíá. Ç éäÝá åßíáé
ðùò åßíáé ÷ñÞóéìï íá áíáëýïõìå ôá äåäïìÝíá ãéá íá äïýìå ðùò Ýìïéáæáí
êÜðïéá äåäïìÝíç ÷ñïíéêÞ óôéãìÞ. Ç Temporal SQL åßíáé Ýíá paper ôïõ
Äåêåìâñßïõ ôïõ 1994 áðü ôïí Rick Snodgrass ðïõ ðåñéãñÜöåé áõôÝò ôéò
Ýííïéåò.
Ç X3 áíáêïéíþíåé ôçí Ýãêñéóç åíüò ÍÝïõ ¸ñãïõ, ISO/IEC 9075 ÌÝñïò 7ï: Ç
SQL/Temporal åßíáé ìéá äçìïóßåõóç ôýðïõ ó÷åôéêÞ ìå ôçí SQL/Temporal.
----------------------------------------------------------------------------
Temporal SQL
************
Rick Snodgrass (ðñüåäñïò ôçò åðéôñïðÞò TSQL2)
31-Äåê-1994
Áñêåôïß áìöéóâÞôçóáí ôçí áíÜãêç áõîçìÝíçò õðïóôÞñéîçò ÷ñüíïõ óôçí SQL3
(üðùò áõôü ðñïôåßíåôáé áðü ôï DBL RIO-75, üðïõ êáé æçôÜ Ýíá íÝï ôìÞìá
ôçò SQL ðïõ íá õðïóôçñßæåé ÷ñïíéêÝò (temporal) âÜóåéò). Ï éó÷õñéóìüò
ôïõò âáóßæåôáé óôï üôé ïé áöçñçìÝíïé ôýðïé äåäïìÝíùí (abstract data
types -ADT's) áñêïýí ãéá ÷ñïíéêÞ õðïóôÞñéîç. Óå áõôü ôï ðëçñïöïñéáêü
êåßìåíï, äéáöùíþ, êáé, ÷ñçóéìïðïéþíôáò áäéÜóåéóôá ðáñáäåßãìáôá,
äåß÷íù ðùò ÷ñçóéìïðïéþíôáò ìüíï óôÞëåò ìå áöçñçìÝíïõò ôýðïõò äåäïìÝíùí
äåí áñêåß ãéá ÷ñïíéêÝò åñùôÞóåéò. Åéäéêüôåñá, ðïëëÝò êïéíÝò ÷ñïíéêÝò
åñùôÞóåéò, åßíáé åßôå äýóêïëåò íá ðñïóïìïéùèïýí ìå SQL, åßôå áðáéôïýí
ôçí åíóùìÜôùóç SQL óå ìéá äéáäéêáóôéêÞ (procedural) ãëþóóá. Ïé
åíáëëáêôéêÝò ëýóåéò åêöñÜæïíôáé óå TSQL2, ìéá ÷ñïíéêÞ åðÝêôáóç óôçí
SQL-92.
[1m23.16.1. ÅÉÓÁÃÙÃÇ[0m
Ç õðïóôÞñéîç Ýãêõñïõ ÷ñüíïõ (Valid-time) îåðåñíÜåé áõôÞ åíüò êïéíïý
÷ñïíéêïý áöçñçìÝíïõ ôýðïõ äåäïìÝíùí (ADT). Óôïí ôåëåõôáßï, ìéá óôÞëç
ðñïóäéïñßæåôáé óáí Ýíá ÷ñïíéêü ðåäßï, åßôå ùò DATE åßôå ùò INTERVAL
(èá äïèïýí ðáñáäåßãìáôá óýíôïìá). Ìå ôïí Ýãêõñï ÷ñüíï, ïé ãñáììÝò
åíüò ðßíáêá äéáöïñïðïéïýíôáé ìå ôï ðÝñáóìá ôïõ ÷ñüíïõ, êáèþò
äéáöïñïðïéåßôáé êáé ç ðñáãìáôéêüôçôá. Ç ÷ñïíéêÞ óöñáãßäá (timestamp)
ðïõ ó÷åôßæåôáé ìå ìéá ãñáììÞ åíüò ðßíáêá Ýãêõñùí ÷ñüíùí (valid-time
table) ìåôáöñÜæåôáé áðü ôçí ãëþóóá åñùôÞóåùí ùò ç ÷ñïíéêÞ óôéãìÞ ãéá
ôçí ïðïßá ï óõíäõáóìüò ôéìþí ôùí óôçëþí ôçò ãñáììÞò åêåßíçò Þôáí
Ýãêõñïò. Ç ýðáñîç ôçò Ýììåóçò áõôÞò ÷ñïíéêÞò óöñáãßäáò åðéôñÝðåé ôçí
äéáôýðùóç óáöþí êáé ðñùôüôõðùí åñùôÞóåùí.
[1m23.16.2. ÌÉÁ ÌÅËÅÔÇ- ÁÐÏÈÇÊÅÕÓÇ ÓÕÃ×ÑÏÍÙÍ/ÔÑÅ×ÏÕÓÙÍ ÐËÇÑÏÖÏÑÉÙÍ[0m
Ôï Ãñáöåßï Ðñïóùðéêïý ôïõ Ðáíåðéóôçìßïõ ôçò Áñéæüíá Ý÷åé êÜðïéåò
ðëçñïöïñßåò óå ìéá âÜóç äåäïìÝíùí, ìÝóá óôéò ïðïßåò êáé ôï üíïìá ôùí
õðáëëÞëùí, ôïí ôñÝ÷ïíôá ìéóèü ôïõò, êáé ôïí ôñÝ÷ïõóá èÝóç ôïõò. Áõôü
ìðïñåß íá ðåñéãñáöåß ìå Ýíáí áðëü ðßíáêá.
Employee(Name, Salary, Title)
ÄåäïìÝíïõ áõôïý ôïõ ðßíáêá, ç åýñåóç ôïõ ìéóèïý åíüò õðáëëÞëïõ åßíáé
åýêïëç.
SELECT Salary
FROM Employee
WHERE Name = 'Bob'
Ôþñá ôï Ãñáöåßï Ðñïóùðéêïý åðéèõìåß íá êáôáãñÜöåé êáé ôçí çìåñïìçíßá
ãÝííçóçò. Ãéá íá ôï êÜíåé, ðñïóèÝôåé ìéá óôÞëç óôïí ðßíáêá, êáé Ýôóé
ðñïêýðôåé ôï áêüëïõèï ó÷Þìá.
Employee(Name, Salary, Title, DateofBirth DATE)
Ç åýñåóç ôùí ãåíåèëßùí åíüò õðáëëÞëïõ åßíáé áíÜëïãç ìå ôï íá âñïýìå ôï
ìéóèü ôïõ.
SELECT DateofBirth
FROM Employee
WHERE Name = 'Bob'
[1m23.16.3. ÌÅËÅÔÇ - ÁÐÏÈÇÊÅÕÓÇ ÉÓÔÏÑÉÊÙÍ ÐËÇÑÏÖÏÑÉÙÍ[0m
Ôï Ãñáöåßï Ðñïóùðéêïý åðéèõìåß ðåñÜóåé ôá éóôïñéêÜ óôïé÷åßá ôùí
õðáëëÞëùí óå çëåêôñïíéêÞ ìïñöÞ. Ãéá íá ôï êÜíåé, ðñïóèÝôïõí äýï
óôÞëåò, ìéá ðïõ õðïäåéêíýåé ðüôå Ýãéíå Ýãêõñç ç ðëçñïöïñßá ôçò
ãñáììÞò, êáé ìéá ãéá ôï ðüôå Ýðáøå íá éó÷ýåé.
Employee (Name, Salary, Title, DateofBirth, Start DATE, Stop DATE)
Óôï ìïíôÝëï äåäïìÝíùí, áõôÝò ïé äýï óôÞëåò åßíáé ðáñüìïéåò ìå ôï
DateofBirth. Ðáñüëá áõôÜ, ç ðáñïõóßá ôïõò Ý÷åé åðéðôþóåéò ìåãÜëçò
êëßìáêáò.
[1m23.16.4. ÌÅËÅÔÇ - ÐÑÏÂÏËÇ (PROJECTION)[0m
Ãéá íá âñïýìå ôïí ôñÝ÷ïíôá ìéóèü åíüò õðáëëÞëïõ, ôá ðñÜãìáôá åßíáé
ðëÝïí äõóêïëüôåñá.
SELECT Salary
FROM Employee
WHERE Name = 'Bob' êáé Start <= CURRENT_DATE êáé CURRENT_DATE <= Stop
ÁõôÞ ç åñþôçóç åßíáé ðéï óýíèåôç áðü üôé ç ðñïçãïýìåíç. Ç äõóêïëßá
åßíáé ðñïöáíþò ïé äýï íÝåò óôÞëåò. Ôï Ãñáöåßï Ðñïóùðéêïý èÝëåé íá
äéáíÝìåé óå êÜèå õðÜëëçëï ôï ìéóèïëïãéêü ôïõ áñ÷åßï. Åéäéêüôåñá, ãéá
êÜèå Ýíáí, èá ðñÝðåé íá êáèïñéóôïýí ôá ìÝãéóôá äéáóôÞìáôá áíÜ ìéóèü.
Äõóôõ÷þò, áõôü äåí åßíáé äõíáôü ìå SQL. ¸íáò õðÜëëçëïò Ý÷åé Ýíá ôõ÷áßï
áñéèìü áëëáãþí èÝóåùí ìåôáîý ìéóèïëïãéêþí áëëáãþí.
Name Salary Title DateofBirth Start Stop
---- ------ ----- ----------- ----- ----
Bob 60000 Assistant Provost 1945-04-09 1993-01-01 1993-05-30
Bob 70000 Assistant Provost 1945-04-09 1993-06-01 1993-09-30
Bob 70000 Provost 1945-04-09 1993-10-01 1994-01-31
Bob 70000 Professor 1945-04-09 1994-02-01 1994-12-31
Åéêüíá 1
Óçìåéþóôå ðùò õðÜñ÷ïõí ôñåéò ãñáììÝò üðïõ ï ìéóèüò ôïõ Bob ðáñÝìåéíå
óôáèåñüò óôéò $70,000. Ãé áõôü ôï áðïôÝëåóìá èá Ýðñåðå íá äþóåé äýï
ãñáììÝò ãéá ôïí Bob.
Name Salary Start Stop
---- ------ ----- ----
Bob 60000 1993-01-01 1993-05-30
Bob 70000 1993-06-01 1994-12-31
Ìéá åíáëëáêôéêÞ ëýóç åßíáé íá äïèåß óôïí ÷ñÞóôç ìéá åêôýðùóç
ðëçñïöïñéþí Ìéóèïý êáé Ôßôëïõ, êáé íá áöÞíïõìå ôïí ÷ñÞóôç íá êáèïñßæåé
ðüôå Üëëáîå ï ìéóèüò ôïõ. Ç åíáëëáêôéêÞ áõôÞ äåí åßíáé ðïëý èåëêôéêÞ Þ
ñåáëéóôéêÞ. Ìéá äåýôåñç, åßíáé íá ÷ñçóéìïðïéÞóïõìå üóï ðéï ðïëý SQL
ãßíåôáé.
CREATE TABLE Temp(Salary, Start, Stop)
AS SELECT Salary, Start, Stop
FROM Employee;
åðáíáëÜâáôå
UPDATE Temp T1
SET (T1.Stop) = (SELECT MAX(T2.Stop)
FROM Temp AS T2
WHERE T1.Salary = T2.Salary êáé T1.Start < T2.Start
êáé T1.Stop >= T2.Start êáé T1.Stop < T2.Stop)
WHERE EXISTS (SELECT *
FROM Temp AS T2
WHERE T1.Salary = T2.Salary êáé T1.Start < T2.Start
êáé T1.Stop >= T2.Start êáé T1.Stop < T2.Stop)
ìÝ÷ñé íá ìçí åíçìåñùèåß êáìéÜ ãñáììÞ;
DELETE FROM Temp T1
WHERE EXISTS (SELECT *
FROM Temp AS T2
WHERE T1.Salary = T2.Salary
êáé ((T1.Start > T2.Start êáé T1.Stop <= T2.Stop)
OR (T1.Start >= T2.Start êáé T1.Stop < T2.Stop))
Ï âñüã÷ïò âñßóêåé ôá äéáóôÞìáôá åêåßíá ðïõ åðéêáëýðôïíôáé Þ åßíáé
ãåéôïíéêÜ êáé ãé áõôü èá Ýðñåðå íá óõã÷ùíåõèïýí. Ï âñü÷ïò åêôåëåßôáé N
öïñÝò óôçí ÷åéñüôåñç ðåñßðôùóç, üðïõ ôï N åßíáé ï áñéèìüò ôùí ãñáììþí
óå ìéá áëõóßäá åðéêáëõðôüìåíùí Þ ãåéôïíéêþí ãñáììþí ìå ßóåò ôéìÝò. Ï
áíáãíþóôçò ìðïñåß íá ðñïóïìïéþóåé ôçí åñþôçóç ôïõ ðßíáêá ôïõ
ðáñáäåßãìáôïò ãéá íá ðåéóôåß ãéá ôçí ïñèüôçôá ôïõ ðáñáðÜíù.
Ìéá ôñßôç åíáëëáêôéêÞ åßíáé íá ÷ñçóéìïðïéÞóïõìå SQL ìüíï ãéá íá
áíïßîïõìå Ýíá êÝñóïñá (cursor) óôïí ðßíáêá. Ìéá óõíäåäåìÝíç ëßóôá
÷ñïíéêþí ðåñéüäùí èá êñáôçèåß, êÜèå ìéá Ý÷ïíôáò êáé Ýíá ìéóèü. Ç
óõíäåäåìÝíç ëßóôá áñ÷éêïðïéåßôáé êåíÞ.
DECLARE emp_cursor CURSOR FOR
SELECT Salary, Title, Start, Stop
FROM Employee;
OPEN emp_cursor;
loop:
FETCH emp_cursor INTO :salary, :start, :stop;
if no-data returned then goto finished;
find position in linked list to insert this information;
goto loop;
finished:
CLOSE emp_cursor;
äéÝôñåîå ôç ëßóôá ôõðþíïíôáò çìåñïìçíßåò êáé ìéóèïýò
Ç óõíäåäåìÝíç ëßóôá ìðïñåß êáé íá ìçí ÷ñåéÜæåôáé óôçí ðåñßðôùóç áõôÞ
áíÜ ï êÝñóïñáò åßíáé ORDER BY Start.
Óå êÜèå ðåñßðôùóç, ç åñþôçóç, ðïõ åßíáé êáé öõóéêÞ, åßíáé äýóêïëï íá
åêöñáóôåß ìå ôéò õðÜñ÷ïõóåò äõíáôüôçôåò ôçò SQL-92. Ç åñþôçóç åßíáé
ôåôñéììÝíç óå TSQL2.
SELECT Salary
FROM Employee
[1m23.16.5. ÌÅËÅÔÇ - ÓÕÓ×ÅÔÉÓÌÏÓ (JOIN)[0m
Ìéá ðéï äñáóôéêÞ ðñïóÝããéóç åßíáé íá áðïöýãïõìå ôï ðñüâëçìá ôçò
åîáãùãÞò ôçò ìéóèïëïãéêÞò éóôïñßáò ìå áíáäéïñãÜíùóç ôïõ ó÷Þìáôïò þóôå
íá áðïóõæåýîïõìå ôï ìéóèü, ôç èÝóç êáé ôçí çìåñïìçíßá ãÝííçóçò
(ðáñáêÜôù, áãíïïýìå ôçí çìåñïìçíßá ãÝííçóçò, ãéá áðëüôçôá).
Employee1 (Name, Salary, Start DATE, Stop DATE)
Employee2 (Name, Title, Start DATE, Stop DATE)
Ï ðßíáêáò Employee1 Ý÷åé ùò áêïëïýèùò.
Name Salary Start Stop
---- ------ ----- ----
Bob 60000 1993-01-01 1993-05-30
Bob 70000 1993-06-01 1993-12-31
Åäþ åßíáé êáé ï ðßíáêáò Employee2 ôïõ ðáñáäåßãìáôïò.
Name Title Start Stop
---- ------ ----- ----
Bob Assistant Provost 1993-01-01 1993-09-30
Bob Provost 1993-10-01 1994-01-31
Bob Professor 1994-02-01 1994-12-31
Ìå áõôÞ ôçí áëëáãÞ, ç áðüêôçóç ôçò ðëçñïöïñßáò ôïõ ìéóèïý ãéá Ýíáí
õðÜëëçëï åßíáé ðëÝïí åýêïëç.
SELECT Salary, Start, Stop
FROM Employee1
WHERE Name = 'Bob'
ÁëëÜ ôé èá ãßíåé åÜí ôï Ãñáöåßï Ðñïóùðéêïý èåëÞóåé Ýíáí ðßíáêá ìéóèïý,
äéáóôçìÜôùí èÝóçò (äçëáäÞ, áò õðïèÝóïõìå ðùò ôï Ã.Ð. èÝëåé Ýíáí ðßíáêá
ôçò ìïñöÞò ôçò Åéêüíáò 1); Ìéá åíáëëáêôéêÞ ëýóç åßíáé íá ôõðþóïõìå
ôïõò äýï ðßíáêåò êáé íá áöÞóïõìå ôïí ÷ñÞóôç íá õðïëïãßóåé ôïõò
óõíäõáóìïýò. Ìéá äåýôåñç åíáëëáêôéêÞ, åßíáé íá ÷ñçóéìïðïéÞóïõìå ìüíï
SQL. Äõóôõ÷þò, ç åñþôçóç áõôÞ ðñÝðåé íá êÜíåé ìéá áíÜëõóç êáôáóôÜóåùí
ôïõ ðùò ìéá ãñáììÞ ôïõ Employee1 åðéêáëýðôåé ãñáììÝò ôïõ Employee2.
ÕðÜñ÷ïõí ôÝóóåñéò äõíáôÝò êáôáóôÜóåéò.
SELECT Employee1.Name, Salary, Dept, Employee1.Start, Employee1.Stop
FROM Employee1, Employee2
WHERE Employee1.Name = Employee2.Name
and Employee2.Start <= Employee1.Start and Employee1.Stop < Employee2.Stop
UNION
SELECT Employee1.Name, Salary, Dept, Employee1.Start, Employee2.Stop
FROM Employee1, Employee2
WHERE Employee1.Name = Employee2.Name
and Employee1.Start >= Employee2.Start and Employee2.Stop < Employee1.Stop
êáé Employee1.Start < Employee2.Stop
UNION
SELECT Employee1.Name, Salary, Dept, Employee2.Start, Employee1.Stop
FROM Employee1, Employee2
WHERE Employee1.Name = Employee2.Name
and Employee2.Start > Employee1.Start and Employee1.Stop < Employee2.Stop
and Employee2.Start < Employee1.Stop
UNION
SELECT Employee1.Name, Salary, Dept, Employee2.Start, Employee2.Stop
FROM Employee1, Employee2
WHERE Employee1.Name = Employee2.Name
and Employee2.Start > Employee1.Start and Employee2.Stop < Employee1.Stop
Ôï íá ðéÜóïõìå ôéò ôÝóóåñéò êáôáóôÜóåéò åßíáé ìéá äýóêïëç êáé
åíäéáöÝñïõóá åñãáóßá. Óå TSQL2, ôï íá êÜíïõìå Ýíá ÷ñïíéêü óõó÷åôéóìü
(temporal join) åßíáé üðùò êÜðïéïò èá ðåñßìåíå.
SELECT Employee1.Name, Salary, Dept
FROM Employee1, Employee2
WHERE Employee1.Name = Employee2.Name
[1m23.16.6. ÌÅËÅÔÇ - ÁÈÑÏÉÓÔÉÊÏÉ ÔÅËÅÓÔÅÓ (AGGREGATES)[0m
Ôþñá ôï Ã.Ð. åñùôÜôáé, ðïéïò åßíáé ï ìÝãéóôïò ìéóèüò; Ðñéí ôçí
åéóáãùãÞ ôïõ ÷ñüíïõ, áõôü Þôáí åýêïëï.
SELECT MAX(Salary)
FROM Employee
Ôþñá üìùò ðïõ ç ìéóèïëïãéêÞ éóôïñßá áðïèçêåýåôáé, èá èÝëáìå ìéá
éóôïñßá ôïõ ìÝãéóôïõ ìéóèïý áíÜ ôïí ÷ñüíï. Ôï ðñüâëçìá öõóéêÜ åßíáé,
ðùò ç SQL äåí ðáñÝ÷åé ÷ñïíéêïýò áèñïéóôéêïýò ôåëåóôÝò. Ï åýêïëïò
ôñüðïò íá ãßíåé ôï ðáñáðÜíù, åßíáé íá ôõðþóïõìå ôçí ðëçñïöïñßá êáé íá
ôçí äéáôñÝîïõìå ÷åéñïêßíçôá ãéá ôá ìÝãéóôá. ÅíáëëáêôéêÜ, èá ìðïñïýóáìå
íá êÜíïõìå ôå÷íÜóìáôá êáé íá ìåôáôñÝøïõìå ôçí áèñïéóôéêÞ åñþôçóç óå
ìéá ìéá ìç áèñïéóôéêÞ, êáé ìåôÜ áõôÞ óå ÷ñïíéêÞ. Ç ìç áèñïéóôéêÞ èá
Ýâñéóêå åêåßíïõò ôïõò ìéóèïýò ãéá ôïõò ïðïßïõò äåí õðÜñ÷åé ìåãáëýôåñïò
ìéóèüò.
SELECT Salary
FROM Employee AS E1
WHERE NOT EXISTS (SELECT *
FROM Employee AS E2
WHERE E2.Salary > E1.Salary)
Ç ìåôáôñïðÞ ìéáò ôÝôïéáò åñþôçóçò áðÝ÷åé ðïëý áðü ôï íá èåùñçèåß
ôåôñéììÝíç. Ôï áêüëïõèï åßíáé ìéá ðñïóÝããéóç.
CREATE TABLE Temp (Salary, Start, Stop)
AS SELECT Salary, Start, Stop
FROM Employee;
INSERT INTO Temp
SELECT T.Salary, T.Start, E.Start
FROM Temp AS T, Employee AS E
WHERE E.Start >= T.Start and E.Start < T.Stop and E.Salary > T.Salary;
INSERT INTO Temp
SELECT T.Salary, T.Stop, E.Stop
FROM Temp AS T, Employee AS E
WHERE E.Stop > T.Start and E.Stop <= T.Stop and E.Salary > T.Salary;
DELETE FROM Temp T
WHERE EXISTS (SELECT *
FROM Employee AS E
WHERE ((T.Start => E.Start and T.Start < E.Stop)
OR (E.Start >= T.Start and E.Start < T.Stop))
êáé E.Salary > T.Salary;
ÁõôÞ ç ðñïóÝããéóç äçìéïõñãåß Ýíáí âïçèçôéêü ðßíáêá. ÐñïóèÝôïõìå óå
áõôüí ôïí ðßíáêá ôçí ÷áìçëüôåñç ðåñßïäï áðü ìéá áöáßñåóç äéáóôçìÜôùí
êáé ôçí ìåãáëýôåñç ðåñßïäï áðü ìéá áöáßñåóç äéáóôçìÜôùí. ÌåôÜ
äéáãñÜöïõìå üëåò ôéò ðåñéüäïõò ðïõ åðéêáëýðôïíôáé ìå êÜðïéá ãñáììÞ ðïõ
ïñßæåôáé áðü ôçí õðü-åñþôçóç (subquery), êáé ìÝíïõí ïé NOT EXISTS.
ÔåëéêÜ, äçìéïõñãïýìå áðü ôïí âïçèçôéêü ðßíáêá ôá ìÝãéóôá äéáóôÞìáôá,
ìå ôïí ßäéï ôñüðï ðïõ õðïëïãßóôçêå ðáñáðÜíù ç ðëçñïöïñßá ìéóèþí. ¼ðùò
ìðïñïýìå íá öáíôáóôïýìå, ôÝôïéïò êþäéêáò SQL åßíáé õðåñâïëéêÜ
áíáðïôåëåóìáôéêüò ãéá íá åêôåëåóôåß, äåäïìÝíïõ ôùí óýíèåôùí
öùëéáóìÝíùí (nested) õðïåñùôÞóåùí ìå ôïõò ôåëåóôÝò óýãêñéóçò ìå
êñéôÞñéá áíéóüôçôáò.
Ìéá ôñßôç åíáëëáêôéêÞ ëýóç, åßíáé íá ÷ñçóéìïðïéÞóïõìå SQL üóï ëéãüôåñï
ãßíåôáé, êáé íá õðïëïãßóïõìå ôçí åðéèõìçôÞ éóôïñéêüôçôá áðü ìÝãéóôåò
ôéìÝò óå ìéá Üëëç ãëþóóá ÷ñçóéìïðïéþíôáò åíóùìáôùìÝíïõò êÝñóïñåò.
Ç åñþôçóç óå TSQL2 åßíáé áðëïýóôáôç.
SELECT MAX(Salary)
FROM Employee
[1m23.16.7. ÐÅÑÉËÇØÇ[0m
Ïé ðåñéóóüôåñåò åöáñìïãÝò ìå âÜóç äåäïìÝíùí Ý÷ïõí íá áíôéìåôùðßóïõí
êáé äåäïìÝíá ìå ÷ñïíéêÞ äéáêýìáíóç åßíáé áíÜãêç íá áíôéìåôùðéóôïýí . Ç
õðïóôÞñéîç Ýãêõñïõ-÷ñüíïõ åßíáé áðïýóá óôçí SQL. ÐïëëÝò êïéíÝò
÷ñïíéêÝò åñùôÞóåéò åßíáé ëïéðüí åßôå äýóêïëåò íá åîïìïéùèïýí ìÝóù SQL,
Þ áðáéôïýí åíóùìÜôùóç ôçò SQL óå ìéá äçëùôéêÞ / äéáäéêáóôéêÞ ãëþóóá
(procedural), ëüãù ôçò Ýëëåéøçò õðïóôÞñéîçò ðéíÜêùí Ýãêõñïõ-÷ñüíïõ óôï
ìïíôÝëï äåäïìÝíùí êáé óôçí êáôáóêåõÞ åñùôÞóåùí ôçò SQL.
Óå Üëëï óçìåßï, äåßîáìå ðùò ç õðïóôÞñéîç Ýãêõñïõ-÷ñüíïõ áðáéôåß ìéêñÝò
áëëáãÝò óôçí õëïðïßçóç ôçò DBMS, êáé ìðïñåß íá áðëïðïéÞóåé äñáìáôéêÜ
êÜðïéåò åñùôÞóåéò, íá êÜíåé äõíáôÝò Üëëåò, êáé áêïëïýèùò íá åðéôñÝøåé
ìåèüäïõò äåéêôïäüôçóçò êáé óôñáôçãéêÝò âåëôéóôïðïéÞóåùí ðïõ ìðïñïýí íá
ïäçãÞóïõí óå óçìáíôéêÝò êáëõôåñåýóåéò áðüäïóçò.
Ìå ôï íÝï ôìÞìá ôçò SQL3 ðïõ õðïóôçñßæåé ðëçñïöïñßåò ìå ÷ñïíéêÞ
äéáêýìáíóç, ìðïñïýìå íá áñ÷ßóïõìå íá óôï÷åýïõìå óå ôÝôïéåò åöáñìïãÝò,
åðéôñÝðïíôáò óôçí SQL3 íá äéá÷åéñßæåôáé êáëýôåñá ôá ÷ñïíéêÜ äåäïìÝíá.
----------------------------------------------------------------------------
ÅðéôñïðÞ Åðéêýñùóçò Ðñïôýðùí* X3, Ôå÷íïëïãßá Ðëçñïöïñéþí
ÄÇÌÏÓÉÅÕÓÇ ÍÅÙÍ
Áñ. ÅããñÜöïõ: PR/96-0002
ÁðÜíôçóç åéò: Barbara Bennett óôï bbennett@itic.nw.dc.us
Ç X3 áíáêïéíþíåé ôçí ¸ãêñéóç åíüò ÍÝïõ ¸ñãïõ, ISO/IEC
9075 ÔìÞìá 7: SQL/Temporal
Washington D.C., ÉáíïõÜñéïò 1996
----------------------------------------------------------------------------
-- ÅðéôñïðÞ Åðéêýñùóçò Ðñïôýðùí X3, Ôå÷íïëïãßá Ðëçñïöïñéþí áíáêïéíþíåé
ôçí Ýãêñéóç åíüò ÍÝïõ ¸ñãïõ óôçí ÷ñïíéêÞ õðïóôÞñéîç SQL
(SQL/Temporal), ISO/IEC 9075 ÔìÞìá 7. Ï óêïðüò ôïõ ðñïôåéíüìåíïõ
ðñïôýðïõ ðñïóäéïñßæåé Ýíá íÝï ÔìÞìá óôï áíåñ÷üìåíï ðñüôõðï SQL3, ð.÷.,
ôï ÔìÞìá 7, ×ñïíéêÞ SQL, ùò åðåêôÜóåéò ôçò ãëþóóáò SQL ðïõ
õðïóôçñßæïõí ôçí áíÜêôçóç , êáé åðåîåñãáóßá ÷ñïíéêþí äåäïìÝíùí óå Ýíá
ðåñéâÜëëïí ìéáò SQL âÜóçò äåäïìÝíùí. Ç åðüìåíç óõíåäñßá X3H2
ðñïãñáììáôßóôçêå ãéá ôéò 11-14 Ìáñôßïõ ôïõ 1996 óôï ÊÜíóáò.
ÅñùôÞóåéò ãéá ôï Ýñãï áõôü èá ðñÝðåé íá óôáëïýí óôï
Chairman of X3H2,
Dr. Donald R. Deutsch,
Sybase, Inc., Suite 800,
6550 Rock Spring
Drive, Bethesda, MD 20817.
Email: deutsch@sybase.com.
Ìéá áñ÷éêÞ ðñüóêëçóç ãéá ðáôÝíôåò êáé ó÷åôéêÜ èÝìáôá (ðíåõìáôéêÝò
éäéïêôçóßåò, åìðïñéêÜ óÞìáôá) (copyrights, trademarks) åêäßäåôáé áõôüí
ôïí êáéñü. ÕðïâÜëåôå ðëçñïöïñßåò ãéá ôá èÝìáôá áõôÜ óôï
X3 Secretariat at
1250 Eye Street
NW, Suite 200,
Washington DC 20005.
Email: x3sec@itic.nw.dc.us
FAX: (202)638-4922.
[1m23.17. ÔìÞìá 8 - ISO/ANSI ÐÏËÕÌÅÓÁ SQL (SQL MULTIMEDIA - SQL/MM)[0m
¸íá íÝï äéåèíÝò Ýñãï ôõðïðïßçóçò ISO/IEC ãéá ôçí áíÜðôõîç ìéáò
âéâëéïèÞêçò êëÜóåùí SQL (SQL class library) ãéá åöáñìïãÝò ðïëõìÝóùí
åãêñßèçêå áðü ôéò áñ÷Ýò ôïõ 1993. ÁõôÞ ç íÝá äñáóôçñéüôçôá
ôõðïðïßçóçò, ïíïìáæüìåíç SQL Multimedia (SQL/MM), èá êáèïñßóåé ðáêÝôá
ìå ïñéóìïýò áöçñçìÝíùí ôýðùí äåäïìÝíùí SQL (abstract data type- ADT)
÷ñçóéìïðïéþíôáò ôéò åõêïëßåò ãéá ôïí êáèïñéóìü ôïõ ADT êáé ôçí
ðñüêëçóç ðïõ ðáñÝ÷åôáé óôéò áíáìåíüìåíåò ðñïäéáãñáöÝò ôïõ SQL3. Ôï
SQL/MM Ý÷åé óáí óôü÷ï íá ôõðïðïéÞóåé ôéò âéâëéïèÞêåò êëÜóåùí ãéá ôçí
åðéóôÞìç êáé ìç÷áíéêÞ, ôçí full-text åðåîåñãáóßá êåéìÝíïõ, êáé ôéò
ìåèüäïõò ãéá äéá÷åßñéóç áíôéêåéìÝíùí ðïëõìÝóùí üðùò åéêüíá, Þ÷ïò,
animation, ìïõóéêÞ, êáé âßíôåï. Èá ðáñÝ÷åé ðéèáíÜ Ýíá SQL language
binding áíôéêåßìåíï ðïëõìÝóùí áðü Üëëåò JTC1 ïñãáíþóåéò ðñïôõðïðïßçóçò
(ð.÷. SC18 ãéá êåßìåíá, SC24 ãéá åéêüíåò, êáé SC29 ãéá öùôïãñáößåò êáé
êéíïýìåíåò åéêüíåò).
Ôï ðëÜíï áõôïý ôïõ Ýñãïõ ãéá ôï SQL/MM äåß÷íåé üôé èá åßíáé Ýíá
óðïíäõëùôü ðñüôõðï ðïõ èá áðïôåëåßôáé áðü Ýíá áõîáíüìåíï áñéèìü
ôìçìÜôùí. Ôï ôìÞìá 1 èá åßíáé Ýíá Ðëáßóéï (Framework) ðïõ èá
ðñïóäéïñßæåé ðùò èá êáôáóêåõáóôïýí ôá õðüëïéðá ìÝñç. ÊÜèå Ýíá áðü ôá
õðüëïéðá ìÝñç, èá åßíáé áöïóéùìÝíï óå Ýíá óõãêåêñéìÝíï ðáêÝôï SQL
åöáñìïãþí. Ç ðáñáêÜôù äïìÞ ôìçìÜôùí ôïõ SQL/MM õðÜñ÷åé áðü ôïí
Áýãïõóôï ôïõ 1994:
· ÔìÞìá 1: Ðëáßóéï. Ìç ôå÷íéêÞ ðåñéãñáöÞ ôïõ ðùò äïìåßôáé ôï êåßìåíï.
· ÔìÞìá 2: ÌÝèïäïé ÊåéìÝíïõ êáé ADTs ãéá åðåîåñãáóßá äåäïìÝíùí
êåéìÝíïõ. Ðåñß ôéò 45 óåëßäåò.
· ÔìÞìá 3: ×ùñéêÝò ÌÝèïäïé êáé ADTs ãéá äéá÷åßñéóç ÷ùñéêþí äåäïìÝíùí.
Ðåñß ôéò 200 óåëßäåò ìå óõíåéóöïñÝò áðü åéäéêïýò óôá ÷ùñéêÜ
äåäïìÝíá, áðü ïñãáíþóåéò 3 ÷ùñþí.
· ÔìÞìá 4: Ìåèüäïõò Ãåíéêïý Óêïðïý êáé ADTs ãéá ìéãáäéêïýò áñéèìïýò.
Ïé äõíáôüôçôåò ðåñéëáìâÜíïõí ôñéãùíïìåôñéêÝò êáé åêèåôéêÝò
óõíáñôÞóåéò, äéáíýóìáôá, óýíïëá, êëð. Ðñïò ôï ðáñüí ðåñß ôéò 90
óåëßäåò.
õðÜñ÷åé Ýíá ðëÞèïò óôÜíôáñ åñãáóéþí óôïí ôïìÝá ôïí ×ùñéêþí êáé
Ãåùãñáöéêþí ÓõóôçìÜôùí:
· ANSI X3L1 - Geographic Information Systems. Mark Ashworth of
Unisys is the liason between X3L1 êáé ANSI X3H2. He is also the
editor for parts 1, 3, êáé 4 of the SQL/MM draft.
· ISO TC 211 - Geographic information/Geomatics
[1m24. Ôå÷íéêÞ õðïóôÞñéîç ãéá ôçí PostgreSQL[0m
Áí Ý÷åôå ïðïéáäÞðïôå ôå÷íéêÞ åñþôçóç Þ óõíáíôÞóåôå ïðïéïäÞðïôå
ðñüâëçìá ìðïñåßôå íá óôåßëåôå e-mail óôï:
· pgsql-questions@postgresql.org
êáé íá ðåñéìÝíåôå áðÜíôçóç ìå e-mail óå ëéãüôåñï áðü ìéá ìÝñá.
Êáèþò ç âÜóç ôùí ÷ñçóôþí óôï internet åßíáé ôåñÜóôéá, êáé ïé
÷ñÞóôåò õðïóôçñßæïõí ôïõò Üëëïõò ÷ñÞóôåò, ôï internet èá åßíáé
éêáíü íá äþóåé åýêïëá ôå÷íéêÞ õðïóôÞñéîç óå äéóåêáôïììýñéá ÷ñÞóôåò.
Ç õðïóôÞñéîç ìå Email åßíáé ðïëý ðéï âïëéêÞ áðü ôçí ôçëåöùíéêÞ
õðïóôÞñéîç êáèþò ìðïñåßôå íá êÜíåôå cut êáé paste ôá ìçíýìáôá
ëáèþí, ôçí Ýîïäï ôïõ ðñïãñÜììáôïò êëð. êáé íá ôï ìåôáäþóåôå åýêïëá
óôç ëßóôá áëëçëïãñáößáò/newsgroup.
Óôï ðñïóå÷Ýò ìÝëëïí, ï ïñãáíéóìüò ôçò PostgreSQL èá ðïõëÜ ôå÷íéêÞ
õðïóôÞñéîç óå ìåãÜëåò/ìéêñÝò åôáéñåßåò, ôá Ýóïäá ðïõ èá ðñïêýøïõí èá
÷ñçóéìïðïéçèïýí ãéá ôç óõíôÞñçóç áñêåôþí mirror sites (web êáé ftp) óå
üëï ôïí êüóìï. Èá ÷ñçóéìïðïéçèïýí åðßóçò ãéá ôçí ðáñáãùãÞ åêôõðùìÝíçò
ôåêìçñßùóçò, âïçèçìÜôùí, âéâëßùí ðïõ èá âïçèÞóïõí ôïõò ðåëÜôåò.
Ìðïñåßôå åðßóçò íá âïçèçèåßôå áðü óõìâïõëåõôéêÝò åôáéñåßåò üðùò ç
Anderson, WGS (Work Group Solutions). ÅðéêïéíùíÞóôå ìáæß ôïõò ãéá
âïÞèåéá -
· Work Group Solutions <http://www.wgs.com>
· Anderson Consulting <http://www.ac.com>
[1m25. ÏéêïíïìéêÜ êáé ÅðáããåëìáôéêÜ ÈÝìáôá[0m
Ïé åìðïñéêÝò âÜóåéò ðëçñþíïõí ðïëëïýò öüñïõò, åíäåéêôéêÜ áíáöÝñïõìå :
ïìïóðïíäéáêïýò, ðïëéôåéáêïýò, ðùëÞóåùí, åñãáóéáêïýò, êïéíùíéêÞò
áóöÜëåéáò, éáôñéêÞò ðåñßèáëøçò åñãáæïìÝíùí, èÝëãçôñùí ãéá ôïõò
åñãáæüìåíïõò, êüóôç ãéá marketing êáé äéáöÞìéóç. ¼ëá áõôÜ ôá Ýîïäá äåí
ðçãáßíïõí êáôåõèåßáí ãéá ôçí áíÜðôõîç ôçò âÜóçò. ¼ôáí áãïñÜæåôå ìéá
åìðïñéêÞ âÜóç, ìÝñïò ôçò ôéìÞò ðçãáßíåé ãéá åðéâáñýíóåéò üðùò öüñïé,
Ýîïäá êáé ôï éóïæýãéï ôïõ êüóôïõò ôçò âÜóçò R&D.
Ïé åìðïñéêÝò âÜóåéò, åðßóçò, ðñÝðåé íá ðëçñþóïõí ãéá êôßñéá/êôßóìáôá
êáé íá áãïñÜóïõí ìç÷áíÝò Unix, íá ôéò åãêáôáóôÞóïõí êáé íá ôéò
óõíôçñÞóïõí. ¼ëá áõôÜ ôá Ýîïäá åðéâáñýíïõí ôåëéêÜ ôïí ðåëÜôç.
Ç PostgreSQL õðåñÝ÷åé Ýíáíôé ôùí åìðïñéêþí âÜóåùí ìéá êáé äåí
ðëçñþíïõí Üìåóá öüñïõò êáèþò áíáðôýóóåôáé ìÝóù internet. ¸íá ôåñÜóôéï
ðëÞèïò áíèñþðùí óõíåéóöÝñåé óôçí áíÜðôõîç ôçò PostgreSQL. Ãéá
ðáñÜäåéãìá, óå ìéá õðïèåôéêÞ ðåñßðôùóç, áí õðÜñ÷ïõí Ýíá åêáôïììýñéï
åôáéñåßåò óôçí ÁìåñéêÞ êáé êÜèå ìéá óõíåéóöÝñåé 10 $ (áîßá ôïõ
ëïãéóìéêïý PostgreSQL) ôüôå êÜèå ìßá èá ëÜâåé äÝêá åêáôïììýñéá
äïëÜñéá!! ÁõôÞ åßíáé ç [1mÌÁÃÅÉÁ [22môçò áíÜðôõîçò ëïãéóìéêïý óôï internet.
ÌÝ÷ñé ôþñá, ï ðçãáßïò êþäéêáò ôçò PostgreSQL åßíáé ðåñßðïõ 2,00,000
ãñáììÝò óå êþäéêá "C", "C++". Áí ôï êüóôïò êÜèå ãñáììÞò êþäéêá "C"
åßíáé $ 2 ôüôå ôï óõíïëéêü êüóôïò ôçò PostgreSQL èá Þôáí óÞìåñá $
4,00,000 (ôåôñáêüóéåò ÷éëéÜäåò äïëÜñéá!).
ÐïëëÝò åôáéñåßåò Þäç áíáðôýóóïõí ôåñÜóôéåò ðïóüôçôåò êþäéêá "C",
"C++". ¸ôóé, ôï íá ðÜñïõí ôïí ðçãáßï êþäéêá ôçò PostgreSQL êáé íá
óõíåñãáóôïýí ìå Üëëåò åôáéñåßåò óôï internet èá ùöåëÞóåé ôçí åôáéñåßá
íá åîïéêïíïìÞóåé ÷ñüíï êáé ðñïóðÜèåéá.
[1m26. Ëßóôá Üëëùí âÜóåùí äåäïìÝíùí[0m
ÐáñáêÜôù áêïëïõèåß ëßóôá Üëëùí SQL âÜóåùí äåäïìÝíùí ãéá Unix, Linux.
· ÐáôÞóôå êáé ðçãáßíåôå óôï Applications->databases.
<http://www.caldera.com/tech-ref/linuxapps/linapps.html>
· ÐáôÞóôå êáé ðçãáßíåôå óôï Applications->databases.
<http://www.xnet.com/~blatura/linapps.shtml>
· ÐçãÝò ãéá ÂÜóåéò ÄåäïìÝíùí <http://linas.org/linux/db.html>
ãñÜöôçêå áðü ôïí Linas Vepstas: linas@fc.net
· Ëßóôá äùñåÜí âÜóåùí
<http://cuiwww.unige.ch:80/~scg/FreeDB/FreeDB.list.html>
· Ëßóôá RDBMS ôïõ Browne <http://www.hex.net/~cbbrowne/rdbms.html>
ãñÜöôçêå áðü ôïí Christopher B. Browne cbbrowne@hex.net
· Ëßóôá Ó÷åóéáêþí DBMS ôïõ SAL <http://SAL.KachinaTech.COM/H/1/>
· Ëßóôá Áíôéêåéìåíïóôñáöþí DBMS ôïõ SAL
<http://SAL.KachinaTech.COM/H/2/>
· Ëßóôá âïçèçôéêþí åöáñìïãþí êáé Üëëùí âÜóåùò ôïõ SAL
<http://SAL.KachinaTech.COM/H/3/>
· ACM SIGMOD. Äåßêôçò ôïõ äçìüóéá äéáèÝóéìïõ ëïãéóìéêïý ÂÜóåùí
ÄåäïìÝíùí <http://bunny.cs.uiuc.edu/sigmod/databaseSoftware/>
[1m27. ×ñÞóéìåò óõìâïõëÝò ãéá áíáæçôÞóåéò óôï Internet World Wide Web[0m
Ôï Internet åßíáé áðÝñáíôï, õðÜñ÷åé óå áõôü ôåñÜóôéá ðïóüôçôá
ëïãéóìéêïý êáé ìéá èÜëáóóá ðëçñïöïñéþí áðü êÜôù ôïõ. ÁõîÜíåôáé ìå
ñõèìü 300% åôçóßùò óå üëï ôïí êüóìï. Õðïëïãßæåôáé üôé õðÜñ÷ïõí ðåñßðïõ
10 åêáôïììýñéá Web sites óå üëç ôç ãç!
Ãéá íá øÜîåôå ãéá ðëçñïöïñßåò èá ÷ñçóéìïðïéÞóåôå ìç÷áíÝò áíáæÞôçóçò
üðùò ôï "Yahoo", "Netscape", "Lycos" êëð. Ðçãáßíåôå óôï Yahoo êáé
ðáôÞóôå óôï search. ×ñçóéìïðïéÞóôå ôéò åðéëïãÝò öéëôñáñßóìáôïò ãéá íá
óõãêåêñéìåíïðïéÞóåôå ôá êñéôÞñéá áíáæÞôçóçò. Ç default åðéëïãÞ
áíáæÞôçóçò åßíáé ç "¸îõðíç áíáæÞôçóç" ("Intelligent search") ðïõ åßíáé
ðéï ãåíéêÞ êáé åìöáíßæåé üëåò ôéò ðéèáíüôçôåò. ÐáôÞóôå óôéò "ÅðéëïãÝò"
("Options") ãéá íá äéáëÝîåôå áíáæÞôçóç ìå "áêñéâÞ öñÜóç"("EXACT
phrase"), áíáæÞôçóç ìå "AND", ìå "OR", êëð. Ìå áõôüí ôïí ôñüðï èá
âñåßôå ôéò ðëçñïöïñßåò ðïõ èÝëåôå ðïëý ãñçãïñüôåñá.
[1m28. ÓõìðÝñáóìá[0m
ÌåôÜ áðü Ýñåõíá óå üëåò ôéò äéáèÝóéìåò âÜóåéò ðïõ åßíáé [1mÄÙÑÅÁÍ [22mêáé ï
ðçãáßïò ôïõò êþäéêáò åßíáé äéáèÝóéìïò, êáôáëÞîáìå üôé ÌÏÍÏ ç
PostgreSQL åßíáé ç ÐÅÑÉÓÓÏÔÅÑÏ þñéìç, ÐÅÑÉÓÓÏÔÅÑÏ åõñÝùò äéáäåäïìÝíç
êáé éó÷õñÞ, äùñåÜí âÜóç RDBMS SQL (áíôéêåéìåíïóôñáöÞò-ó÷åóéáêÞ), óôïí
êüóìï.
Ç PostgreSQL åßíáé éäéáßôåñá åëêõóôéêÞ ìéá êáé Ý÷åé Þäç ãßíåé áñêåôÞ
äïõëåéÜ, êáé Ý÷åé ïäçãïýò ODBC, JDBC ìå ôïõò ïðïßïõò åßíáé äõíáôü íá
ãñÜøåôå åöáñìïãÝò áíåîáñôÞôùò âÜóçò. Ïé åöáñìïãÝò ðïõ ãñÜöïíôáé óôçí
PostgreSQL ìå ÷ñÞóç ïäçãþí ODBC, JDBC åßíáé åýêïëá ìåôáöÝñóéìåò óå
Üëëåò âÜóåéò, üðùò Oracle, Sybase êáé Informix. Åðßóçò, åöáñìïãÝò ðïõ
Ý÷ïõí ãñáöôåß óå Oracle, Sybase êáé Informix ìå ÷ñÞóç ïäçãþí ODBC,
JDBC åßíáé åýêïëá ìåôáöÝñóéìåò óôçí PostgreSQL.
Ìðïñåß íá áíáñùôçèåßôå "ÁëëÜ ãéáôß PostgreSQL ;" Ç áðÜíôçóç åßíáé üôé
ìéá êáé ÷ñåéÜæåôáé ðïëý ðåñéóóüôåñïò ÷ñüíïò ãéá íá áíáðôõ÷èåß Ýíá íÝï
óýóôçìá âÜóçò áðü ôçí áñ÷Þ, åßíáé ëïãéêü íá äéáëÝîïõìå Ýíá óýóôçìá
âÜóçò äåäïìÝíùí ðïõ éêáíïðïéåß ôéò ðáñáêÜôù óõíèÞêåò -
¸íá óýóôçìá âÜóçò äåäïìÝíùí
· ôïõ ïðïßïõ ï ðçãáßïò êþäéêáò åßíáé äéáèÝóéìïò
· ðïõ äåí Ý÷åé ðåñéïñéóìïýò óå èÝìáôá Üäåéáò, Þ êÜðïéá ðñïóáñôçìÝíç
éäéïêôçóßá óå áõôü
· ôï ïðïßï äéáíÝìåôáé ìÝóù internet
· ôï ïðïßï áíáðôýóóåôáé åäþ êáé ðïëëÜ ÷ñüíéá.
· ôï ïðïßï éêáíïðïéåß ìåëëïíôéêÝò áíÜãêåò üðùò ôçí SQL 3 (SQL 98)
· ôï ïðïßï Ý÷åé åîåëéãìÝíåò äõíáôüôçôåò
êáé áðëÜ óõìâáßíåé íá åßíáé ç 'PostgreSQL' ðïõ éêáíïðïéåß üëåò
áõôÝò ôéò óõíèÞêåò êáé íá åßíáé ôï êáôÜëëçëï ëïãéóìéêü ãéá áõôÞ ôçí
ðåñßðôùóç.
[1m29. Óõ÷íÜ ÄéáôõðùìÝíåò ÅñùôÞóåéò ó÷åôéêÜ ìå ôçí PostgreSQL[0m
Ðçãáßíåôå óôçí ôåëåõôáßá Ýêäïóç ôïõ FAQ ãéá General, Linux êáé Irix
óôï
· <http://www.postgresql.org/docs/faq-english.shtml>
[1m30. Óçìåßùóç Ðíåõìáôéêþí ÄéêáéùìÜôùí[0m
ÐíåõìáôéêÞ éäéïêôçóßá (c) 1997 ôïõ Al Dev (Alavoor Vasudevan). ¼ëá ôá
äéêáéþìáôá Ý÷ïõí êáôï÷õñùèåß.
ÊÁÌÉÁ ÅÕÈÕÍÇ ÃÉÁ ÅÐÁÊÏËÏÕÈÏÌÅÍÅÓ ÆÇÌÉÅÓ. Óå êáìßá ðåñßðôùóç ï
óõããñáöÝáò ôïõ êåéìÝíïõ äåí åßíáé õðåýèõíïò ãéá ïðïéáäÞðïôå æçìéÜ
(óõìðåñéëáìâáíïìÝíùí ÷ùñßò ðåñéïñéóìü, ôùí åéäéêþí, áíáðÜíôå÷ùí,
åðáêüëïõèùí, Þ Üìåóùí/ Ýììåóùí æçìéþí, ðñïóùðéêþí âëáâþí, áðþëåéá
åðáããåëìáôéêþí êåñäþí, äéáêïðÞ åñãáóßáò, áðþëåéá åðáããåëìáôéêþí
äåäïìÝíùí, Þ ïðïéáäÞðïôå ÷ñçìáôéêÞ áðþëåéá) ðïõ ðñïêýøåé áðü ôç ÷ñÞóç
áõôïý ôïõ êåéìÝíïõ.
Ï óõããñáöÝáò äåí åããõÜôáé ôçí ïñèüôçôá, ÷ñçóéìüôçôá, åìðïñéêüôçôá ôïõ
êåéìÝíïõ. Ïé ìÜñêåò, åôáéñåßåò êáé ôá ïíüìáôá ôùí ðñïúüíôùí ðïõ
áíáöÝñïíôáé óå áõôü ôï êåßìåíï åßíáé óÞìá êáôáôåèÝí ôùí áíôßóôïé÷ùí
éäéïêôçôþí. Óáò ðáñáðÝìðïõìå óôá îå÷ùñéóôÜ óçìåéþìáôá ðíåõìáôéêÞò
éäéïêôçóßáò ôùí åôáéñåéþí êáé ðñïúüíôùí ðïõ áíáöÝñèçêáí óå áõôü ôï
êåßìåíï. Åßíáé äéêÞ óáò åõèýíç íá äéáâÜóåôå êáé íá êáôáëÜâåôå ôá
óçìåéþìáôá ðíåõìáôéêÞò éäéïêôçóßáò ôùí ïñãáíéóìþí /åôáéñåéþí/ðñïúüíôùí
/óõããñáöÝùí ðïõ áíáöÝñèçêáí óå áõôü ôï êåßìåíï ðñéí íá ÷ñçóéìïðïéÞóåôå
ôéò áíôßóôïé÷åò ðëçñïöïñßåò.
[1mAE. ÐáñÜñôçìá A - Óýíôáîç ôïõ ANSI/ISO SQL 1992[0m
Áõôü ôï áñ÷åßï ðåñéÝ÷åé ôï äåíäñïåéäÞ äéáäñïìÞ ìå ðñïôåñáéüôçôá âÜèïõò (depth-first tree traversal) ôïõ BNF ãéá ôç ãëþóóá, ðïõ ïëïêëçñþèçêå óôéò 27-ÁÕÃ-1992 11:03:41.64.
Ç óõãêåêñéìÝíç Ýêäïóç ôïõ BNF ðïõ ðåñéëáìâÜíåôáé åäþ åßíáé ç: ANSI-only, SQL2-only.
<SQL terminal character> ::=
<SQL language character>
| <SQL embedded language character>
<SQL language character> ::=
<simple Latin letter>
| <digit>
| <SQL special character>
<simple Latin letter> ::=
<simple Latin upper case letter>
| <simple Latin lower case letter>
<simple Latin upper case letter> ::=
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O
| P | Q | R | S | T | U | V | W | X | Y | Z
<simple Latin lower case letter> ::=
a | b | c | d | e | f | g | h | i | j | k | l | m | n | o
| p | q | r | s | t | u | v | w | x | y | z
<digit> ::=
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
<SQL special character> ::=
<space>
| <double quote>
| <percent>
| <ampersand>
| <quote>
| <left paren>
| <right paren>
| <asterisk>
| <plus sign>
| <comma>
| <minus sign>
| <period>
| <solidus>
| <colon>
| <semicolon>
| <less than operator>
| <equals operator>
| <greater than operator>
| <question mark>
| <underscore>
| <vertical bar>
<space> ::= !! <EMPHASIS>(space character in character set in use)
<double quote> ::= "
<percent> ::= %
<ampersand> ::= &
<quote> ::= '
<left paren> ::= (
<right paren> ::= )
<asterisk> ::= *
<plus sign> ::= +
<comma> ::= ,
<minus sign> ::= -
<period> ::= .
<solidus> ::= /
<colon> ::= :
<semicolon> ::= ;
<less than operator> ::= <
<equals operator> ::= =
<greater than operator> ::= >
<question mark> ::= ?
<underscore> ::= _
<vertical bar> ::= |
<SQL embedded language character> ::=
<left bracket>
| <right bracket>
<left bracket> ::= [
<right bracket> ::= ]
<token> ::=
<nondelimiter token>
| <delimiter token>
<nondelimiter token> ::=
<regular identifier>
| <key word>
| <unsigned numeric literal>
| <national character string literal>
| <bit string literal>
| <hex string literal>
<regular identifier> ::= <identifier body>
<identifier body> ::=
<identifier start> [ ( <underscore> | <identifier part> )... ]
<identifier start> ::= <EMPHASIS>(!! See the Syntax Rules)
<identifier part> ::=
<identifier start>
| <digit>
<key word> ::=
<reserved word>
| <non-reserved word>
<reserved word> ::=
ABSOLUTE | ACTION | ADD | ALL
| ALLOCATE | ALTER | AND
| ANY | ARE
| AS | ASC
| ASSERTION | AT
| AUTHORIZATION | AVG
| BEGIN | BETWEEN | BIT | BIT_LENGTH
| BOTH | BY
| CASCADE | CASCADED | CASE | CAST
| CATALOG
| CHAR | CHARACTER | CHAR_LENGTH
| CHARACTER_LENGTH | CHECK | CLOSE | COALESCE
| COLLATE | COLLATION
| COLUMN | COMMIT
| CONNECT
| CONNECTION | CONSTRAINT
| CONSTRAINTS | CONTINUE
| CONVERT | CORRESPONDING | COUNT | CREATE | CROSS
| CURRENT
| CURRENT_DATE | CURRENT_TIME
| CURRENT_TIMESTAMP | CURRENT_USER | CURSOR
| DATE | DAY | DEALLOCATE | DEC
| DECIMAL | DECLARE | DEFAULT | DEFERRABLE
| DEFERRED | DELETE | DESC | DESCRIBE | DESCRIPTOR
| DIAGNOSTICS
| DISCONNECT | DISTINCT | DOMAIN | DOUBLE | DROP
| ELSE | END | END-EXEC | ESCAPE
| EXCEPT | EXCEPTION
| EXEC | EXECUTE | EXISTS
| EXTERNAL | EXTRACT
| FALSE | FETCH | FIRST | FLOAT | FOR
| FOREIGN | FOUND | FROM | FULL
| GET | GLOBAL | GO | GOTO
| GRANT | GROUP
| HAVING | HOUR
| IDENTITY | IMMEDIATE | IN | INDICATOR
| INITIALLY | INNER | INPUT
| INSENSITIVE | INSERT | INT | INTEGER | INTERSECT
| INTERVAL | INTO | IS
| ISOLATION
| JOIN
| KEY
| LANGUAGE | LAST | LEADING | LEFT
| LEVEL | LIKE | LOCAL | LOWER
| MATCH | MAX | MIN | MINUTE | MODULE
| MONTH
| NAMES | NATIONAL | NATURAL | NCHAR | NEXT | NO
| NOT | NULL
| NULLIF | NUMERIC
| OCTET_LENGTH | OF
| ON | ONLY | OPEN | OPTION | OR
| ORDER | OUTER
| OUTPUT | OVERLAPS
| PAD | PARTIAL | POSITION | PRECISION | PREPARE
| PRESERVE | PRIMARY
| PRIOR | PRIVILEGES | PROCEDURE | PUBLIC
| READ | REAL | REFERENCES | RELATIVE | RESTRICT
| REVOKE | RIGHT
| ROLLBACK | ROWS
| SCHEMA | SCROLL | SECOND | SECTION
| SELECT
| SESSION | SESSION_USER | SET
| SIZE | SMALLINT | SOME | SPACE | SQL | SQLCODE
| SQLERROR | SQLSTATE
| SUBSTRING | SUM | SYSTEM_USER
| TABLE | TEMPORARY
| THEN | TIME | TIMESTAMP
| TIMEZONE_HOUR | TIMEZONE_MINUTE
| TO | TRAILING | TRANSACTION
| TRANSLATE | TRANSLATION | TRIM | TRUE
| UNION | UNIQUE | UNKNOWN | UPDATE | UPPER | USAGE
| USER | USING
| VALUE | VALUES | VARCHAR | VARYING | VIEW
| WHEN | WHENEVER | WHERE | WITH | WORK | WRITE
| YEAR
| ZONE
<non-reserved word> ::=
ADA
| C | CATALOG_NAME
| CHARACTER_SET_CATALOG | CHARACTER_SET_NAME
| CHARACTER_SET_SCHEMA | CLASS_ORIGIN | COBOL | COLLATION_CATALOG
| COLLATION_NAME | COLLATION_SCHEMA | COLUMN_NAME | COMMAND_FUNCTION
| COMMITTED
| CONDITION_NUMBER | CONNECTION_NAME | CONSTRAINT_CATALOG | CONSTRAINT_NAME
| CONSTRAINT_SCHEMA | CURSOR_NAME
| DATA | DATETIME_INTERVAL_CODE
| DATETIME_INTERVAL_PRECISION | DYNAMIC_FUNCTION
| FORTRAN
| LENGTH
| MESSAGE_LENGTH | MESSAGE_OCTET_LENGTH | MESSAGE_TEXT | MORE | MUMPS
| NAME | NULLABLE | NUMBER
| PASCAL | PLI
| REPEATABLE | RETURNED_LENGTH | RETURNED_OCTET_LENGTH | RETURNED_SQLSTATE
| ROW_COUNT
| SCALE | SCHEMA_NAME | SERIALIZABLE | SERVER_NAME | SUBCLASS_ORIGIN
| TABLE_NAME | TYPE
| UNCOMMITTED | UNNAMED
<unsigned numeric literal> ::=
<exact numeric literal>
| <approximate numeric literal>
<exact numeric literal> ::=
<unsigned integer> [ <period> [ <unsigned integer> ] ]
| <period> <unsigned integer>
<unsigned integer> ::= <digit>...
<approximate numeric literal> ::= <mantissa> E <exponent>
<mantissa> ::= <exact numeric literal>
<exponent> ::= <signed integer>
<signed integer> ::= [ <sign> ] <unsigned integer>
<sign> ::= <plus sign> | <minus sign>
<national character string literal> ::=
N <quote> [ <character representation>... ] <quote>
[ ( <separator>... <quote> [ <character representation>... ] <quote> )... ]
<character representation> ::=
<nonquote character>
| <quote symbol>
<nonquote character> ::= !! <EMPHASIS>(See the Syntax Rules.)
<quote symbol> ::= <quote><quote>
<separator> ::= ( <comment> | <space> | <newline> )...
<comment> ::=
<comment introducer> [ <comment character>... ] <newline>
<comment introducer> ::= <minus sign><minus sign>[<minus sign>...]
<comment character> ::=
<nonquote character>
| <quote>
<newline> ::= !! <EMPHASIS>(implementation-defined end-of-line indicator)
<bit string literal> ::=
B <quote> [ <bit>... ] <quote>
[ ( <separator>... <quote> [ <bit>... ] <quote> )... ]
<bit> ::= 0 | 1
<hex string literal> ::=
X <quote> [ <hexit>... ] <quote>
[ ( <separator>... <quote> [ <hexit>... ] <quote> )... ]
<hexit> ::= <digit> | A | B | C | D | E | F | a | b | c | d | e | f
<delimiter token> ::=
<character string literal>
| <date string>
| <time string>
| <timestamp string>
| <interval string>
| <delimited identifier>
| <SQL special character>
| <not equals operator>
| <greater than or equals operator>
| <less than or equals operator>
| <concatenation operator>
| <double period>
| <left bracket>
| <right bracket>
<character string literal> ::=
[ <introducer><character set specification> ]
<quote> [ <character representation>... ] <quote>
[ ( <separator>... <quote> [ <character representation>... ] <quote> )... ]
<introducer> ::= <underscore>
<character set specification> ::=
<standard character repertoire name>
| <implementation-defined character repertoire name>
| <user-defined character repertoire name>
| <standard universal character form-of-use name>
| <implementation-defined universal character form-of-use name>
<standard character repertoire name> ::= <character set name>
<character set name> ::= [ <schema name> <period> ]
<SQL language identifier>
<schema name> ::=
[ <catalog name> <period> ] <unqualified schema name>
<catalog name> ::= <identifier>
<identifier> ::=
[ <introducer><character set specification> ] <actual identifier>
<actual identifier> ::=
<regular identifier>
| <delimited identifier>
<delimited identifier> ::=
<double quote> <delimited identifier body> <double quote>
<delimited identifier body> ::= <delimited identifier part>...
<delimited identifier part> ::=
<nondoublequote character>
| <doublequote symbol>
<nondoublequote character> ::= <EMPHASIS>(!! See the Syntax Rules)
<doublequote symbol> ::= <double quote><double quote>
<unqualified schema name> ::= <identifier>
<SQL language identifier> ::=
<SQL language identifier start>
[ ( <underscore> | <SQL language identifier part> )... ]
<SQL language identifier start> ::= <simple Latin letter>
<SQL language identifier part> ::=
<simple Latin letter>
| <digit>
<implementation-defined character repertoire name> ::=
<character set name>
<user-defined character repertoire name> ::= <character set name>
<standard universal character form-of-use name> ::=
<character set name>
<implementation-defined universal character form-of-use name> ::=
<character set name>
<date string> ::=
<quote> <date value> <quote>
<date value> ::=
<years value> <minus sign> <months value>
<minus sign> <days value>
<years value> ::= <datetime value>
<datetime value> ::= <unsigned integer>
<months value> ::= <datetime value>
<days value> ::= <datetime value>
<time string> ::=
<quote> <time value> [ <time zone interval> ] <quote>
<time value> ::=
<hours value> <colon> <minutes value> <colon> <seconds value>
<hours value> ::= <datetime value>
<minutes value> ::= <datetime value>
<seconds value> ::=
<seconds integer value> [ <period> [ <seconds fraction> ] ]
<seconds integer value> ::= <unsigned integer>
<seconds fraction> ::= <unsigned integer>
<time zone interval> ::=
<sign> <hours value> <colon> <minutes value>
<timestamp string> ::=
<quote> <date value> <space> <time value>
[ <time zone interval> ] <quote>
<interval string> ::=
<quote> ( <year-month literal> | <day-time literal> ) <quote>
<year-month literal> ::=
<years value>
| [ <years value> <minus sign> ] <months value>
<day-time literal> ::=
<day-time interval>
| <time interval>
<day-time interval> ::=
<days value>
[ <space> <hours value> [ <colon> <minutes value>
[ <colon> <seconds value> ] ] ]
<time interval> ::=
<hours value> [ <colon> <minutes value> [ <colon> <seconds value> ] ]
| <minutes value> [ <colon> <seconds value> ]
| <seconds value>
<not equals operator> ::= <>
<greater than or equals operator> ::= >=
<less than or equals operator> ::= <=
<concatenation operator> ::= ||
<double period> ::= ..
<module> ::=
<module name clause>
<language clause>
<module authorization clause>
[ <temporary table declaration>... ]
<module contents>...
<module name clause> ::=
MODULE [ <module name> ]
[ <module character set specification> ]
<module name> ::= <identifier>
<module character set specification> ::=
NAMES ARE <character set specification>
<language clause> ::=
LANGUAGE <language name>
<language name> ::=
ADA | C | COBOL | FORTRAN | MUMPS | PASCAL | PLI
<module authorization clause> ::=
SCHEMA <schema name>
| AUTHORIZATION <module authorization identifier>
| SCHEMA <schema name>
AUTHORIZATION <module authorization identifier>
<module authorization identifier> ::=
<authorization identifier>
<authorization identifier> ::= <identifier>
<temporary table declaration> ::=
DECLARE LOCAL TEMPORARY TABLE
<qualified local table name>
<table element list>
[ ON COMMIT ( PRESERVE | DELETE ) ROWS ]
<qualified local table name> ::=
MODULE <period> <local table name>
<local table name> ::= <qualified identifier>
<qualified identifier> ::= <identifier>
<table element list> ::=
<left paren> <table element> [ ( <comma> <table element> )... ] <right paren>
<table element> ::=
<column definition>
| <table constraint definition>
<column definition> ::=
<column name> ( <data type> | <domain name> )
[ <default clause> ]
[ <column constraint definition>... ]
[ <collate clause> ]
<column name> ::= <identifier>
<data type> ::=
<character string type>
[ CHARACTER SET <character set specification> ]
| <national character string type>
| <bit string type>
| <numeric type>
| <datetime type>
| <interval type>
<character string type> ::=
CHARACTER [ <left paren> <length> <right paren> ]
| CHAR [ <left paren> <length> <right paren> ]
| CHARACTER VARYING <left paren> <length> <right paren>
| CHAR VARYING <left paren> <length> <right paren>
| VARCHAR <left paren> <length> <right paren>
<length> ::= <unsigned integer>
<national character string type> ::=
NATIONAL CHARACTER [ <left paren> <length> <right paren> ]
| NATIONAL CHAR [ <left paren> <length> <right paren> ]
| NCHAR [ <left paren> <length> <right paren> ]
| NATIONAL CHARACTER VARYING <left paren> <length> <right paren>
| NATIONAL CHAR VARYING <left paren> <length> <right paren>
| NCHAR VARYING <left paren> <length> <right paren>
<bit string type> ::=
BIT [ <left paren> <length> <right paren> ]
| BIT VARYING <left paren> <length> <right paren>
<numeric type> ::=
<exact numeric type>
| <approximate numeric type>
<exact numeric type> ::=
NUMERIC [ <left paren> <precision> [ <comma> <scale> ] <right paren> ]
| DECIMAL [ <left paren> <precision> [ <comma> <scale> ] <right paren> ]
| DEC [ <left paren> <precision> [ <comma> <scale> ] <right paren> ]
| INTEGER
| INT
| SMALLINT
<precision> ::= <unsigned integer>
<scale> ::= <unsigned integer>
<approximate numeric type> ::=
FLOAT [ <left paren> <precision> <right paren> ]
| REAL
| DOUBLE PRECISION
<datetime type> ::=
DATE
| TIME [ <left paren> <time precision> <right paren> ]
[ WITH TIME ZONE ]
| TIMESTAMP [ <left paren> <timestamp precision> <right paren> ]
[ WITH TIME ZONE ]
<time precision> ::= <time fractional seconds precision>
<time fractional seconds precision> ::= <unsigned integer>
<timestamp precision> ::= <time fractional seconds precision>
<interval type> ::= INTERVAL <interval qualifier>
<interval qualifier> ::=
<start field> TO <end field>
| <single datetime field>
<start field> ::=
<non-second datetime field>
[ <left paren> <interval leading field precision> <right paren> ]
<non-second datetime field> ::= YEAR | MONTH | DAY | HOUR
| MINUTE
<interval leading field precision> ::= <unsigned integer>
<end field> ::=
<non-second datetime field>
| SECOND [ <left paren> <interval fractional seconds precision> <right paren> ]
<interval fractional seconds precision> ::= <unsigned integer>
<single datetime field> ::=
<non-second datetime field>
[ <left paren> <interval leading field precision> <right paren> ]
| SECOND [ <left paren> <interval leading field precision>
[ <comma> <interval fractional seconds precision> ] <right paren> ]
<domain name> ::= <qualified name>
<qualified name> ::=
[ <schema name> <period> ] <qualified identifier>
<default clause> ::=
DEFAULT <default option>
<default option> ::=
<literal>
| <datetime value function>
| USER
| CURRENT_USER
| SESSION_USER
| SYSTEM_USER
| NULL
<literal> ::=
<signed numeric literal>
| <general literal>
<signed numeric literal> ::=
[ <sign> ] <unsigned numeric literal>
<general literal> ::=
<character string literal>
| <national character string literal>
| <bit string literal>
| <hex string literal>
| <datetime literal>
| <interval literal>
<datetime literal> ::=
<date literal>
| <time literal>
| <timestamp literal>
<date literal> ::=
DATE <date string>
<time literal> ::=
TIME <time string>
<timestamp literal> ::=
TIMESTAMP <timestamp string>
<interval literal> ::=
INTERVAL [ <sign> ] <interval string> <interval qualifier>
<datetime value function> ::=
<current date value function>
| <current time value function>
| <current timestamp value function>
<current date value function> ::= CURRENT_DATE
<current time value function> ::=
CURRENT_TIME [ <left paren> <time precision> <right paren> ]
<current timestamp value function> ::=
CURRENT_TIMESTAMP [ <left paren> <timestamp precision> <right paren> ]
<column constraint definition> ::=
[ <constraint name definition> ]
<column constraint>
[ <constraint attributes> ]
<constraint name definition> ::= CONSTRAINT <constraint name>
<constraint name> ::= <qualified name>
<column constraint> ::=
NOT NULL
| <unique specification>
| <references specification>
| <check constraint definition>
<unique specification> ::=
UNIQUE | PRIMARY KEY
<references specification> ::=
REFERENCES <referenced table and columns>
[ MATCH <match type> ]
[ <referential triggered action> ]
<referenced table and columns> ::=
<table name> [ <left paren> <reference column list> <right paren> ]
<table name> ::=
<qualified name>
| <qualified local table name>
<reference column list> ::= <column name list>
<column name list> ::=
<column name> [ ( <comma> <column name> )... ]
<match type> ::=
FULL
| PARTIAL
<referential triggered action> ::=
<update rule> [ <delete rule> ]
| <delete rule> [ <update rule> ]
<update rule> ::= ON UPDATE <referential action>
<referential action> ::=
CASCADE
| SET NULL
| SET DEFAULT
| NO ACTION
<delete rule> ::= ON DELETE <referential action>
<check constraint definition> ::=
CHECK
<left paren> <search condition> <right paren>
<search condition> ::=
<boolean term>
| <search condition> OR <boolean term>
<boolean term> ::=
<boolean factor>
| <boolean term> AND <boolean factor>
<boolean factor> ::=
[ NOT ] <boolean test>
<boolean test> ::=
<boolean primary> [ IS [ NOT ]
<truth value> ]
<boolean primary> ::=
<predicate>
| <left paren> <search condition> <right paren>
<predicate> ::=
<comparison predicate>
| <between predicate>
| <in predicate>
| <like predicate>
| <null predicate>
| <quantified comparison predicate>
| <exists predicate>
| <unique predicate>
| <match predicate>
| <overlaps predicate>
<comparison predicate> ::=
<row value constructor> <comp op>
<row value constructor>
<row value constructor> ::=
<row value constructor element>
| <left paren> <row value constructor list> <right paren>
| <row subquery>
<row value constructor element> ::=
<value expression>
| <null specification>
| <default specification>
<value expression> ::=
<numeric value expression>
| <string value expression>
| <datetime value expression>
| <interval value expression>
<numeric value expression> ::=
<term>
| <numeric value expression> <plus sign> <term>
| <numeric value expression> <minus sign> <term>
<term> ::=
<factor>
| <term> <asterisk> <factor>
| <term> <solidus> <factor>
<factor> ::=
[ <sign> ] <numeric primary>
<numeric primary> ::=
<value expression primary>
| <numeric value function>
<value expression primary> ::=
<unsigned value specification>
| <column reference>
| <set function specification>
| <scalar subquery>
| <case expression>
| <left paren> <value expression> <right paren>
| <cast specification>
<unsigned value specification> ::=
<unsigned literal>
| <general value specification>
<unsigned literal> ::=
<unsigned numeric literal>
| <general literal>
<general value specification> ::=
<parameter specification>
| <dynamic parameter specification>
| <variable specification>
| USER
| CURRENT_USER
| SESSION_USER
| SYSTEM_USER
| VALUE
<parameter specification> ::=
<parameter name> [ <indicator parameter> ]
<parameter name> ::= <colon> <identifier>
<indicator parameter> ::=
[ INDICATOR ] <parameter name>
<dynamic parameter specification> ::= <question mark>
<variable specification> ::=
<embedded variable name> [ <indicator variable> ]
<embedded variable name> ::=
<colon><host identifier>
<host identifier> ::=
<Ada host identifier>
| <C host identifier>
| <COBOL host identifier>
| <Fortran host identifier>
| <MUMPS host identifier>
| <Pascal host identifier>
| <PL/I host identifier>
<Ada host identifier> ::= !! <EMPHASIS>(See the Syntax Rules.)
<C host identifier> ::=
!! <EMPHASIS>(See the Syntax Rules.)
<COBOL host identifier> ::= !! <EMPHASIS>(See the Syntax Rules.)
<Fortran host identifier> ::= !! <EMPHASIS>(See the Syntax Rules.)
<MUMPS host identifier> ::= !! <EMPHASIS>(See the Syntax Rules.)
<Pascal host identifier> ::= !! <EMPHASIS>(See the Syntax Rules.)
<PL/I host identifier> ::= !! <EMPHASIS>(See the Syntax Rules.)
<indicator variable> ::=
[ INDICATOR ] <embedded variable name>
<column reference> ::= [ <qualifier> <period> ] <column name>
<qualifier> ::=
<table name>
| <correlation name>
<correlation name> ::= <identifier>
<set function specification> ::=
COUNT <left paren> <asterisk> <right paren>
| <general set function>
<general set function> ::=
<set function type>
<left paren> [ <set quantifier> ] <value expression> <right paren>
<set function type> ::=
AVG | MAX | MIN | SUM | COUNT
<set quantifier> ::= DISTINCT | ALL
<scalar subquery> ::= <subquery>
<subquery> ::= <left paren> <query expression> <right paren>
<query expression> ::=
<non-join query expression>
| <joined table>
<non-join query expression> ::=
<non-join query term>
| <query expression> UNION [ ALL ]
[ <corresponding spec> ] <query term>
| <query expression> EXCEPT [ ALL ]
[ <corresponding spec> ] <query term>
<non-join query term> ::=
<non-join query primary>
| <query term> INTERSECT [ ALL ]
[ <corresponding spec> ] <query primary>
<non-join query primary> ::=
<simple table>
| <left paren> <non-join query expression> <right paren>
<simple table> ::=
<query specification>
| <table value constructor>
| <explicit table>
<query specification> ::=
SELECT [ <set quantifier> ] <select list> <table expression>
<select list> ::=
<asterisk>
| <select sublist> [ ( <comma> <select sublist> )... ]
<select sublist> ::=
<derived column>
| <qualifier> <period> <asterisk>
<derived column> ::= <value expression> [ <as clause> ]
<as clause> ::= [ AS ] <column name>
<table expression> ::=
<from clause>
[ <where clause> ]
[ <group by clause> ]
[ <having clause> ]
<from clause> ::= FROM <table reference>
[ ( <comma> <table reference> )... ]
<table reference> ::=
<table name> [ [ AS ] <correlation name>
[ <left paren> <derived column list> <right paren> ] ]
| <derived table> [ AS ] <correlation name>
[ <left paren> <derived column list> <right paren> ]
| <joined table>
<derived column list> ::= <column name list>
<derived table> ::= <table subquery>
<table subquery> ::= <subquery>
<joined table> ::=
<cross join>
| <qualified join>
| <left paren> <joined table> <right paren>
<cross join> ::=
<table reference> CROSS JOIN <table reference>
<qualified join> ::=
<table reference> [ NATURAL ] [ <join type> ] JOIN
<table reference> [ <join specification> ]
<join type> ::=
INNER
| <outer join type> [ OUTER ]
| UNION
<outer join type> ::=
LEFT
| RIGHT
| FULL
<join specification> ::=
<join condition>
| <named columns join>
<join condition> ::= ON <search condition>
<named columns join> ::=
USING <left paren> <join column list> <right paren>
<join column list> ::= <column name list>
<where clause> ::= WHERE <search condition>
<group by clause> ::=
GROUP BY <grouping column reference list>
<grouping column reference list> ::=
<grouping column reference>
[ ( <comma> <grouping column reference> )... ]
<grouping column reference> ::=
<column reference> [ <collate clause> ]
<collate clause> ::= COLLATE <collation name>
<collation name> ::= <qualified name>
<having clause> ::= HAVING <search condition>
<table value constructor> ::=
VALUES <table value constructor list>
<table value constructor list> ::=
<row value constructor> [ ( <comma> <row value constructor> )... ]
<explicit table> ::= TABLE <table name>
<query term> ::=
<non-join query term>
| <joined table>
<corresponding spec> ::=
CORRESPONDING [ BY <left paren> <corresponding column list> <right paren> ]
<corresponding column list> ::= <column name list>
<query primary> ::=
<non-join query primary>
| <joined table>
<case expression> ::=
<case abbreviation>
| <case specification>
<case abbreviation> ::=
NULLIF <left paren> <value expression> <comma>
<value expression> <right paren>
| COALESCE <left paren> <value expression>
( <comma> <value expression> )... <right paren>
<case specification> ::=
<simple case>
| <searched case>
<simple case> ::=
CASE <case operand>
<simple when clause>...
[ <else clause> ]
END
<case operand> ::= <value expression>
<simple when clause> ::= WHEN <when operand> THEN <result>
<when operand> ::= <value expression>
<result> ::= <result expression> | NULL
<result expression> ::= <value expression>
<else clause> ::= ELSE <result>
<searched case> ::=
CASE
<searched when clause>...
[ <else clause> ]
END
<searched when clause> ::= WHEN <search condition> THEN <result>
<cast specification> ::=
CAST <left paren> <cast operand> AS
<cast target> <right paren>
<cast operand> ::=
<value expression>
| NULL
<cast target> ::=
<domain name>
| <data type>
<numeric value function> ::=
<position expression>
| <extract expression>
| <length expression>
<position expression> ::=
POSITION <left paren> <character value expression>
IN <character value expression> <right paren>
<character value expression> ::=
<concatenation>
| <character factor>
<concatenation> ::=
<character value expression> <concatenation operator>
<character factor>
<character factor> ::=
<character primary> [ <collate clause> ]
<character primary> ::=
<value expression primary>
| <string value function>
<string value function> ::=
<character value function>
| <bit value function>
<character value function> ::=
<character substring function>
| <fold>
| <form-of-use conversion>
| <character translation>
| <trim function>
<character substring function> ::=
SUBSTRING <left paren> <character value expression> FROM <start position>
[ FOR <string length> ] <right paren>
<start position> ::= <numeric value expression>
<string length> ::= <numeric value expression>
<fold> ::= ( UPPER | LOWER )
<left paren> <character value expression> <right paren>
<form-of-use conversion> ::=
CONVERT <left paren> <character value expression>
USING <form-of-use conversion name> <right paren>
<form-of-use conversion name> ::= <qualified name>
<character translation> ::=
TRANSLATE <left paren> <character value expression>
USING <translation name> <right paren>
<translation name> ::= <qualified name>
<trim function> ::=
TRIM <left paren> <trim operands> <right paren>
<trim operands> ::=
[ [ <trim specification> ] [ <trim character> ] FROM ] <trim source>
<trim specification> ::=
LEADING
| TRAILING
| BOTH
<trim character> ::= <character value expression>
<trim source> ::= <character value expression>
<bit value function> ::=
<bit substring function>
<bit substring function> ::=
SUBSTRING <left paren> <bit value expression> FROM <start position>
[ FOR <string length> ] <right paren>
<bit value expression> ::=
<bit concatenation>
| <bit factor>
<bit concatenation> ::=
<bit value expression> <concatenation operator> <bit factor>
<bit factor> ::= <bit primary>
<bit primary> ::=
<value expression primary>
| <string value function>
<extract expression> ::=
EXTRACT <left paren> <extract field>
FROM <extract source> <right paren>
<extract field> ::=
<datetime field>
| <time zone field>
<datetime field> ::=
<non-second datetime field>
| SECOND
<time zone field> ::=
TIMEZONE_HOUR
| TIMEZONE_MINUTE
<extract source> ::=
<datetime value expression>
| <interval value expression>
<datetime value expression> ::=
<datetime term>
| <interval value expression> <plus sign> <datetime term>
| <datetime value expression> <plus sign> <interval term>
| <datetime value expression> <minus sign> <interval term>
<interval term> ::=
<interval factor>
| <interval term 2> <asterisk> <factor>
| <interval term 2> <solidus> <factor>
| <term> <asterisk> <interval factor>
<interval factor> ::=
[ <sign> ] <interval primary>
<interval primary> ::=
<value expression primary> [ <interval qualifier> ]
<interval term 2> ::= <interval term>
<interval value expression> ::=
<interval term>
| <interval value expression 1> <plus sign> <interval term 1>
| <interval value expression 1> <minus sign> <interval term 1>
| <left paren> <datetime value expression> <minus sign>
<datetime term> <right paren> <interval qualifier>
<interval value expression 1> ::= <interval value expression>
<interval term 1> ::= <interval term>
<datetime term> ::=
<datetime factor>
<datetime factor> ::=
<datetime primary> [ <time zone> ]
<datetime primary> ::=
<value expression primary>
| <datetime value function>
<time zone> ::=
AT <time zone specifier>
<time zone specifier> ::=
LOCAL
| TIME ZONE <interval value expression>
<length expression> ::=
<char length expression>
| <octet length expression>
| <bit length expression>
<char length expression> ::=
( CHAR_LENGTH | CHARACTER_LENGTH )
<left paren> <string value expression> <right paren>
<string value expression> ::=
<character value expression>
| <bit value expression>
<octet length expression> ::=
OCTET_LENGTH <left paren> <string value expression> <right paren>
<bit length expression> ::=
BIT_LENGTH <left paren> <string value expression> <right paren>
<null specification> ::=
NULL
<default specification> ::=
DEFAULT
<row value constructor list> ::=
<row value constructor element>
[ ( <comma> <row value constructor element> )... ]
<row subquery> ::= <subquery>
<comp op> ::=
<equals operator>
| <not equals operator>
| <less than operator>
| <greater than operator>
| <less than or equals operator>
| <greater than or equals operator>
<between predicate> ::=
<row value constructor> [ NOT ] BETWEEN
<row value constructor> AND <row value constructor>
<in predicate> ::=
<row value constructor>
[ NOT ] IN <in predicate value>
<in predicate value> ::=
<table subquery>
| <left paren> <in value list> <right paren>
<in value list> ::=
<value expression> ( <comma> <value expression> )...
<like predicate> ::=
<match value> [ NOT ] LIKE <pattern>
[ ESCAPE <escape character> ]
<match value> ::= <character value expression>
<pattern> ::= <character value expression>
<escape character> ::= <character value expression>
<null predicate> ::= <row value constructor>
IS [ NOT ] NULL
<quantified comparison predicate> ::=
<row value constructor> <comp op> <quantifier> <table subquery>
<quantifier> ::= <all> | <some>
<all> ::= ALL
<some> ::= SOME | ANY
<exists predicate> ::= EXISTS <table subquery>
<unique predicate> ::= UNIQUE <table subquery>
<match predicate> ::=
<row value constructor> MATCH [ UNIQUE ]
[ PARTIAL | FULL ] <table subquery>
<overlaps predicate> ::=
<row value constructor 1> OVERLAPS <row value constructor 2>
<row value constructor 1> ::= <row value constructor>
<row value constructor 2> ::= <row value constructor>
<truth value> ::=
TRUE
| FALSE
| UNKNOWN
<constraint attributes> ::=
<constraint check time> [ [ NOT ] DEFERRABLE ]
| [ NOT ] DEFERRABLE [ <constraint check time> ]
<constraint check time> ::=
INITIALLY DEFERRED
| INITIALLY IMMEDIATE
<table constraint definition> ::=
[ <constraint name definition> ]
<table constraint> [ <constraint attributes> ]
<table constraint> ::=
<unique constraint definition>
| <referential constraint definition>
| <check constraint definition>
<unique constraint definition> ::=
<unique specification> even in SQL3)
<unique specification>
<left paren> <unique column list> <right paren>
<unique column list> ::= <column name list>
<referential constraint definition> ::=
FOREIGN KEY
<left paren> <referencing columns> <right paren>
<references specification>
<referencing columns> ::=
<reference column list>
<module contents> ::=
<declare cursor>
| <dynamic declare cursor>
| <procedure>
<declare cursor> ::=
DECLARE <cursor name> [ INSENSITIVE ] [ SCROLL ] CURSOR
FOR <cursor specification>
<cursor name> ::= <identifier>
<cursor specification> ::=
<query expression> [ <order by clause> ]
[ <updatability clause> ]
<order by clause> ::=
ORDER BY <sort specification list>
<sort specification list> ::=
<sort specification> [ ( <comma> <sort specification> )... ]
<sort specification> ::=
<sort key> [ <collate clause> ] [ <ordering specification> ]
<sort key> ::=
<column name>
| <unsigned integer>
<ordering specification> ::= ASC | DESC
<updatability clause> ::=
FOR
( READ ONLY |
UPDATE [ OF <column name list> ] )
<dynamic declare cursor> ::=
DECLARE <cursor name> [ INSENSITIVE ] [ SCROLL ] CURSOR
FOR <statement name>
<statement name> ::= <identifier>
<procedure> ::=
PROCEDURE <procedure name>
<parameter declaration list> <semicolon>
<SQL procedure statement> <semicolon>
<procedure name> ::= <identifier>
<parameter declaration list> ::=
<left paren> <parameter declaration>
[ ( <comma> <parameter declaration> )... ] <right paren>
| <parameter declaration>...
<parameter declaration> ::=
<parameter name> <data type>
| <status parameter>
<status parameter> ::=
SQLCODE | SQLSTATE
<SQL procedure statement> ::=
<SQL schema statement>
| <SQL data statement>
| <SQL transaction statement>
| <SQL connection statement>
| <SQL session statement>
| <SQL dynamic statement>
| <SQL diagnostics statement>
<SQL schema statement> ::=
<SQL schema definition statement>
| <SQL schema manipulation statement>
<SQL schema definition statement> ::=
<schema definition>
| <table definition>
| <view definition>
| <grant statement>
| <domain definition>
| <character set definition>
| <collation definition>
| <translation definition>
| <assertion definition>
<schema definition> ::=
CREATE SCHEMA <schema name clause>
[ <schema character set specification> ]
[ <schema element>... ]
<schema name clause> ::=
<schema name>
| AUTHORIZATION <schema authorization identifier>
| <schema name> AUTHORIZATION
<schema authorization identifier>
<schema authorization identifier> ::=
<authorization identifier>
<schema character set specification> ::=
DEFAULT CHARACTER
SET <character set specification>
<schema element> ::=
<domain definition>
| <table definition>
| <view definition>
| <grant statement>
| <assertion definition>
| <character set definition>
| <collation definition>
| <translation definition>
<domain definition> ::=
CREATE DOMAIN <domain name>
[ AS ] <data type>
[ <default clause> ]
[ <domain constraint>... ]
[ <collate clause> ]
<domain constraint> ::=
[ <constraint name definition> ]
<check constraint definition> [ <constraint attributes> ]
<table definition> ::=
CREATE [ ( GLOBAL | LOCAL ) TEMPORARY ] TABLE
<table name>
<table element list>
[ ON COMMIT ( DELETE | PRESERVE ) ROWS ]
<view definition> ::=
CREATE VIEW <table name> [ <left paren> <view column list>
<right paren> ]
AS <query expression>
[ WITH [ <levels clause> ] CHECK OPTION ]
<view column list> ::= <column name list>
<levels clause> ::=
CASCADED | LOCAL
<grant statement> ::=
GRANT <privileges> ON <object name>
TO <grantee> [ ( <comma> <grantee> )... ]
[ WITH GRANT OPTION ]
<privileges> ::=
ALL PRIVILEGES
| <action list>
<action list> ::= <action> [ ( <comma> <action> )... ]
<action> ::=
SELECT
| DELETE
| INSERT [ <left paren> <privilege column list> <right paren> ]
| UPDATE [ <left paren> <privilege column list> <right paren> ]
| REFERENCES [ <left paren> <privilege column list> <right paren> ]
| USAGE
<privilege column list> ::= <column name list>
<object name> ::=
[ TABLE ] <table name>
| DOMAIN <domain name>
| COLLATION <collation name>
| CHARACTER SET <character set name>
| TRANSLATION <translation name>
<grantee> ::=
PUBLIC
| <authorization identifier>
<assertion definition> ::=
CREATE ASSERTION <constraint name> <assertion check>
[ <constraint attributes> ]
<assertion check> ::=
CHECK
<left paren> <search condition> <right paren>
<character set definition> ::=
CREATE CHARACTER SET <character set name>
[ AS ]
<character set source>
[ <collate clause> | <limited collation definition> ]
<character set source> ::=
GET <existing character set name>
<existing character set name> ::=
<standard character repertoire name>
| <implementation-defined character repertoire name>
| <schema character set name>
<schema character set name> ::= <character set name>
<limited collation definition> ::=
COLLATION FROM <collation source>
<collation source> ::=
<collating sequence definition>
| <translation collation>
<collating sequence definition> ::=
<external collation>
| <schema collation name>
| DESC <left paren> <collation name> <right paren>
| DEFAULT
<external collation> ::=
EXTERNAL <left paren> <quote> <external collation name> <quote> <right paren>
<external collation name> ::=
<standard collation name>
| <implementation-defined collation name>
<standard collation name> ::= <collation name>
<implementation-defined collation name> ::= <collation name>
<schema collation name> ::= <collation name>
<translation collation> ::=
TRANSLATION <translation name>
[ THEN COLLATION <collation name> ]
<collation definition> ::=
CREATE COLLATION <collation name> FOR
<character set specification>
FROM <collation source>
[ <pad attribute> ]
<pad attribute> ::=
NO PAD
| PAD SPACE
<translation definition> ::=
CREATE TRANSLATION <translation name>
FOR <source character set specification>
TO <target character set specification>
FROM <translation source>
<source character set specification> ::= <character set specification>
<target character set specification> ::= <character set specification>
<translation source> ::=
<translation specification>
<translation specification> ::=
<external translation>
| IDENTITY
| <schema translation name>
<external translation> ::=
EXTERNAL <left paren> <quote> <external translation name> <quote> <right paren>
<external translation name> ::=
<standard translation name>
| <implementation-defined translation name>
<standard translation name> ::= <translation name>
<implementation-defined translation name> ::= <translation name>
<schema translation name> ::= <translation name>
<SQL schema manipulation statement> ::=
<drop schema statement>
| <alter table statement>
| <drop table statement>
| <drop view statement>
| <revoke statement>
| <alter domain statement>
| <drop domain statement>
| <drop character set statement>
| <drop collation statement>
| <drop translation statement>
| <drop assertion statement>
<drop schema statement> ::=
DROP SCHEMA <schema name> <drop behavior>
<drop behavior> ::= CASCADE | RESTRICT
<alter table statement> ::=
ALTER TABLE <table name> <alter table action>
<alter table action> ::=
<add column definition>
| <alter column definition>
| <drop column definition>
| <add table constraint definition>
| <drop table constraint definition>
<add column definition> ::=
ADD [ COLUMN ] <column definition>
<alter column definition> ::=
ALTER [ COLUMN ] <column name> <alter column action>
<alter column action> ::=
<set column default clause>
| <drop column default clause>
<set column default clause> ::=
SET <default clause>
<drop column default clause> ::=
DROP DEFAULT
<drop column definition> ::=
DROP [ COLUMN ] <column name> <drop behavior>
<add table constraint definition> ::=
ADD <table constraint definition>
<drop table constraint definition> ::=
DROP CONSTRAINT <constraint name> <drop behavior>
<drop table statement> ::=
DROP TABLE <table name> <drop behavior>
<drop view statement> ::=
DROP VIEW <table name> <drop behavior>
<revoke statement> ::=
REVOKE [ GRANT OPTION FOR ]
<privileges>
ON <object name>
FROM <grantee> [ ( <comma> <grantee> )... ] <drop behavior>
<alter domain statement> ::=
ALTER DOMAIN <domain name> <alter domain action>
<alter domain action> ::=
<set domain default clause>
| <drop domain default clause>
| <add domain constraint definition>
| <drop domain constraint definition>
<set domain default clause> ::= SET <default clause>
<drop domain default clause> ::= DROP DEFAULT
<add domain constraint definition> ::=
ADD <domain constraint>
<drop domain constraint definition> ::=
DROP CONSTRAINT <constraint name>
<drop domain statement> ::=
DROP DOMAIN <domain name> <drop behavior>
<drop character set statement> ::=
DROP CHARACTER SET <character set name>
<drop collation statement> ::=
DROP COLLATION <collation name>
<drop translation statement> ::=
DROP TRANSLATION <translation name>
<drop assertion statement> ::=
DROP ASSERTION <constraint name>
<SQL data statement> ::=
<open statement>
| <fetch statement>
| <close statement>
| <select statement: single row>
| <SQL data change statement>
<open statement> ::=
OPEN <cursor name>
<fetch statement> ::=
FETCH [ [ <fetch orientation> ] FROM ]
<cursor name> INTO <fetch target list>
<fetch orientation> ::=
NEXT
| PRIOR
| FIRST
| LAST
| ( ABSOLUTE | RELATIVE ) <simple value specification>
<simple value specification> ::=
<parameter name>
| <embedded variable name>
| <literal>
<fetch target list> ::=
<target specification> [ ( <comma> <target specification> )... ]
<target specification> ::=
<parameter specification>
| <variable specification>
<close statement> ::=
CLOSE <cursor name>
<select statement: single row> ::=
SELECT [ <set quantifier> ] <select list>
INTO <select target list>
<table expression>
<select target list> ::=
<target specification> [ ( <comma> <target specification> )... ]
<SQL data change statement> ::=
<delete statement: positioned>
| <delete statement: searched>
| <insert statement>
| <update statement: positioned>
| <update statement: searched>
<delete statement: positioned> ::=
DELETE FROM <table name>
WHERE CURRENT OF <cursor name>
<delete statement: searched> ::=
DELETE FROM <table name>
[ WHERE <search condition> ]
<insert statement> ::=
INSERT INTO <table name>
<insert columns and source>
<insert columns and source> ::=
[ <left paren> <insert column list> <right paren> ]
<query expression>
| DEFAULT VALUES
<insert column list> ::= <column name list>
<update statement: positioned> ::=
UPDATE <table name>
SET <set clause list>
WHERE CURRENT OF <cursor name>
<set clause list> ::=
<set clause> [ ( <comma> <set clause> )... ]
<set clause> ::=
<object column> <equals operator> <update source>
<object column> ::= <column name>
<update source> ::=
<value expression>
| <null specification>
| DEFAULT
<update statement: searched> ::=
UPDATE <table name>
SET <set clause list>
[ WHERE <search condition> ]
<SQL transaction statement> ::=
<set transaction statement>
| <set constraints mode statement>
| <commit statement>
| <rollback statement>
<set transaction statement> ::=
SET TRANSACTION <transaction mode>
[ ( <comma> <transaction mode> )... ]
<transaction mode> ::=
<isolation level>
| <transaction access mode>
| <diagnostics size>
<isolation level> ::=
ISOLATION LEVEL <level of isolation>
<level of isolation> ::=
READ UNCOMMITTED
| READ COMMITTED
| REPEATABLE READ
| SERIALIZABLE
<transaction access mode> ::=
READ ONLY
| READ WRITE
<diagnostics size> ::=
DIAGNOSTICS SIZE <number of conditions>
<number of conditions> ::= <simple value specification>
<set constraints mode statement> ::=
SET CONSTRAINTS <constraint name list>
( DEFERRED | IMMEDIATE )
<constraint name list> ::=
ALL
| <constraint name> [ ( <comma> <constraint name> )... ]
<commit statement> ::=
COMMIT [ WORK ]
<rollback statement> ::=
ROLLBACK [ WORK ]
<SQL connection statement> ::=
<connect statement>
| <set connection statement>
| <disconnect statement>
<connect statement> ::=
CONNECT TO <connection target>
<connection target> ::=
<SQL-server name>
[ AS <connection name> ]
correspondence with Tony Gordon)
[ USER <user name> ]
| DEFAULT
<SQL-server name> ::= <simple value specification>
<connection name> ::= <simple value specification>
<user name> ::= <simple value specification>
<set connection statement> ::=
SET CONNECTION <connection object>
<connection object> ::=
DEFAULT
| <connection name>
<disconnect statement> ::=
DISCONNECT <disconnect object>
<disconnect object> ::=
<connection object>
| ALL
| CURRENT
<SQL session statement> ::=
<set catalog statement>
| <set schema statement>
| <set names statement>
| <set session authorization identifier statement>
| <set local time zone statement>
<set catalog statement> ::=
SET CATALOG <value specification>
<value specification> ::=
<literal>
| <general value specification>
<set schema statement> ::=
SET SCHEMA <value specification>
<set names statement> ::=
SET NAMES <value specification>
<set session authorization identifier statement> ::=
SET SESSION AUTHORIZATION
<value specification>
<set local time zone statement> ::=
SET TIME ZONE
<set time zone value>
<set time zone value> ::=
<interval value expression>
| LOCAL
<SQL dynamic statement> ::=
<system descriptor statement>
| <prepare statement>
| <deallocate prepared statement>
| <describe statement>
| <execute statement>
| <execute immediate statement>
| <SQL dynamic data statement>
<system descriptor statement> ::=
<allocate descriptor statement>
| <deallocate descriptor statement>
| <set descriptor statement>
| <get descriptor statement>
<allocate descriptor statement> ::=
ALLOCATE DESCRIPTOR <descriptor name>
[ WITH MAX <occurrences> ]
<descriptor name> ::=
[ <scope option> ] <simple value specification>
<scope option> ::=
GLOBAL
| LOCAL
<occurrences> ::= <simple value specification>
<deallocate descriptor statement> ::=
DEALLOCATE DESCRIPTOR <descriptor name>
<set descriptor statement> ::=
SET DESCRIPTOR <descriptor name>
<set descriptor information>
<set descriptor information> ::=
<set count>
| VALUE <item number>
<set item information> [ ( <comma> <set item information> )... ]
<set count> ::=
COUNT <equals operator> <simple value specification 1>
<simple value specification 1> ::= <simple value specification>
<item number> ::= <simple value specification>
<set item information> ::=
<descriptor item name> <equals operator> <simple value specification 2>
<descriptor item name> ::=
TYPE
| LENGTH
| OCTET_LENGTH
| RETURNED_LENGTH
| RETURNED_OCTET_LENGTH
| PRECISION
| SCALE
| DATETIME_INTERVAL_CODE
| DATETIME_INTERVAL_PRECISION
| NULLABLE
| INDICATOR
| DATA
| NAME
| UNNAMED
| COLLATION_CATALOG
| COLLATION_SCHEMA
| COLLATION_NAME
| CHARACTER_SET_CATALOG
| CHARACTER_SET_SCHEMA
| CHARACTER_SET_NAME
<simple value specification 2> ::= <simple value specification>
<item number> ::= <simple value specification>
<get descriptor statement> ::=
GET DESCRIPTOR <descriptor name> <get descriptor information>
<get descriptor information> ::=
<get count>
| VALUE <item number>
<get item information> [ ( <comma> <get item information> )... ]
<get count> ::=
<simple target specification 1> <equals operator>
COUNT
<simple target specification 1> ::= <simple target specification>
<simple target specification> ::=
<parameter name>
| <embedded variable name>
<get item information> ::=
<simple target specification 2> <equals operator> <descriptor item name>>
<simple target specification 2> ::= <simple target specification>
<prepare statement> ::=
PREPARE <SQL statement name> FROM <SQL statement variable>
<SQL statement name> ::=
<statement name>
| <extended statement name>
<extended statement name> ::=
[ <scope option> ] <simple value specification>
<SQL statement variable> ::= <simple value specification>
<deallocate prepared statement> ::=
DEALLOCATE PREPARE <SQL statement name>
<describe statement> ::=
<describe input statement>
| <describe output statement>
<describe input statement> ::=
DESCRIBE INPUT <SQL statement name> <using descriptor>
<using descriptor> ::=
( USING | INTO ) SQL DESCRIPTOR <descriptor name>
<describe output statement> ::=
DESCRIBE [ OUTPUT ] <SQL statement name> <using descriptor>
<execute statement> ::=
EXECUTE <SQL statement name>
[ <result using clause> ]
[ <parameter using clause> ]
<result using clause> ::= <using clause>
<using clause> ::=
<using arguments>
| <using descriptor>
<using arguments> ::=
( USING | INTO ) <argument> [ ( <comma> <argument> )... ]
<argument> ::= <target specification>
<parameter using clause> ::= <using clause>
<execute immediate statement> ::=
EXECUTE IMMEDIATE <SQL statement variable>
<SQL dynamic data statement> ::=
<allocate cursor statement>
| <dynamic open statement>
| <dynamic fetch statement>
| <dynamic close statement>
| <dynamic delete statement: positioned>
| <dynamic update statement: positioned>
<allocate cursor statement> ::=
ALLOCATE <extended cursor name> [ INSENSITIVE ]
[ SCROLL ] CURSOR
FOR <extended statement name>
<extended cursor name> ::=
[ <scope option> ] <simple value specification>
<dynamic open statement> ::=
OPEN <dynamic cursor name> [ <using clause> ]
<dynamic cursor name> ::=
<cursor name>
| <extended cursor name>
<dynamic fetch statement> ::=
FETCH [ [ <fetch orientation> ] FROM ] <dynamic cursor name>
<using clause>
<dynamic close statement> ::=
CLOSE <dynamic cursor name>
<dynamic delete statement: positioned> ::=
DELETE FROM <table name>
WHERE CURRENT OF
<dynamic cursor name>
<dynamic update statement: positioned> ::=
UPDATE <table name>
SET <set clause>
[ ( <comma> <set clause> )... ]
WHERE CURRENT OF
<dynamic cursor name>
<SQL diagnostics statement> ::=
<get diagnostics statement>
<get diagnostics statement> ::=
GET DIAGNOSTICS <sql diagnostics information>
<sql diagnostics information> ::=
<statement information>
| <condition information>
<statement information> ::=
<statement information item> [ ( <comma> <statement information item> )... ]
<statement information item> ::=
<simple target specification> <equals operator> <statement information item name>
<statement information item name> ::=
NUMBER
| MORE
| COMMAND_FUNCTION
| DYNAMIC_FUNCTION
| ROW_COUNT
<condition information> ::=
EXCEPTION <condition number>
<condition information item> [ ( <comma> <condition information item> )... ]
<condition number> ::= <simple value specification>
<condition information item> ::=
<simple target specification> <equals operator> <condition information item name>
<condition information item name> ::=
CONDITION_NUMBER
| RETURNED_SQLSTATE
| CLASS_ORIGIN
| SUBCLASS_ORIGIN
| SERVER_NAME
| CONNECTION_NAME
| CONSTRAINT_CATALOG
| CONSTRAINT_SCHEMA
| CONSTRAINT_NAME
| CATALOG_NAME
| SCHEMA_NAME
| TABLE_NAME
| COLUMN_NAME
| CURSOR_NAME
| MESSAGE_TEXT
| MESSAGE_LENGTH
| MESSAGE_OCTET_LENGTH
<embedded SQL host program> ::=
<embedded SQL Ada program>
| <embedded SQL C program>
| <embedded SQL COBOL program>
| <embedded SQL Fortran program>
| <embedded SQL MUMPS program>
| <embedded SQL Pascal program>
| <embedded SQL PL/I program>
<embedded SQL Ada program> ::= !! <EMPHASIS>(See the Syntax Rules.)
<embedded SQL C program> ::=
!! <EMPHASIS>(See the Syntax Rules.)
<embedded SQL COBOL program> ::= !! <EMPHASIS>(See the Syntax Rules.)
<embedded SQL Fortran program> ::=
!! <EMPHASIS>(See the Syntax Rules.)
<embedded SQL MUMPS program> ::= !! <EMPHASIS>(See the Syntax Rules.)
<embedded SQL Pascal program> ::=
!! <EMPHASIS>(See the Syntax Rules.)
<embedded SQL PL/I program> ::= !! <EMPHASIS>(See the Syntax Rules.)
<embedded SQL declare section> ::=
<embedded SQL begin declare>
[ <embedded character set declaration> ]
[ <host variable definition>... ]
<embedded SQL end declare>
| <embedded SQL MUMPS declare>
<embedded SQL begin declare> ::=
<SQL prefix> BEGIN DECLARE SECTION
[ <SQL terminator> ]
<SQL prefix> ::=
EXEC SQL
| <ampersand>SQL<left paren>
<SQL terminator> ::=
END-EXEC
| <semicolon>
| <right paren>
<embedded character set declaration> ::=
SQL NAMES ARE <character set specification>
<host variable definition> ::=
<Ada variable definition>
| <C variable definition>
| <COBOL variable definition>
| <Fortran variable definition>
| <MUMPS variable definition>
| <Pascal variable definition>
| <PL/I variable definition>
<Ada variable definition> ::=
<Ada host identifier> [ ( <comma> <Ada host identifier> )... ] :
<Ada type specification> [ <Ada initial value> ]
<Ada type specification> ::=
<Ada qualified type specification>
| <Ada unqualified type specification>
<Ada qualified type specification> ::=
SQL_STANDARD.CHAR [ CHARACTER SET
[ IS ] <character set specification> ]
<left paren> 1 <double period> <length> <right paren>
| SQL_STANDARD.BIT
<left paren> 1 <double period> <length> <right paren>
| SQL_STANDARD.SMALLINT
| SQL_STANDARD.INT
| SQL_STANDARD.REAL
| SQL_STANDARD.DOUBLE_PRECISION
| SQL_STANDARD.SQLCODE_TYPE
| SQL_STANDARD.SQLSTATE_TYPE
| SQL_STANDARD.INDICATOR_TYPE
<Ada unqualified type specification> ::=
CHAR
<left paren> 1 <double period> <length> <right paren>
| BIT
<left paren> 1 <double period> <length> <right paren>
| SMALLINT
| INT
| REAL
| DOUBLE_PRECISION
| SQLCODE_TYPE
| SQLSTATE_TYPE
| INDICATOR_TYPE
<Ada initial value> ::=
<Ada assignment operator> <character representation>...
<Ada assignment operator> ::= <colon><equals operator>
<C variable definition> ::=
[ <C storage class> ]
[ <C class modifier> ]
<C variable specification>
<semicolon>
<C storage class> ::=
auto
| extern
| static
<C class modifier> ::= const | volatile
<C variable specification> ::=
<C numeric variable>
| <C character variable>
| <C derived variable>
<C numeric variable> ::=
( long | short | float | double )
<C host identifier> [ <C initial value> ]
[ ( <comma> <C host identifier> [ <C initial value> ] )... ]
<C initial value> ::=
<equals operator> <character representation>...
<C character variable> ::=
char [ CHARACTER SET
[ IS ] <character set specification> ]
<C host identifier>
<C array specification> [ <C initial value> ]
[ ( <comma> <C host identifier>
<C array specification>
[ <C initial value> ] )... ]
<C array specification> ::=
<left bracket> <length> <right bracket>
<C derived variable> ::=
<C VARCHAR variable>
| <C bit variable>
<C VARCHAR variable> ::=
VARCHAR [ CHARACTER SET [ IS ]
<character set specification> ]
<C host identifier>
<C array specification> [ <C initial value> ]
[ ( <comma> <C host identifier>
<C array specification>
[ <C initial value> ] )... ]
<C bit variable> ::=
BIT <C host identifier>
<C array specification> [ <C initial value> ]
[ ( <comma> <C host identifier>
<C array specification>
[ <C initial value> ] )... ]
<COBOL variable definition> ::=
(01|77) <COBOL host identifier> <COBOL type specification>
[ <character representation>... ] <period>
<COBOL type specification> ::=
<COBOL character type>
| <COBOL bit type>
| <COBOL numeric type>
| <COBOL integer type>
<COBOL character type> ::=
[ CHARACTER SET [ IS ]
<character set specification> ]
( PIC | PICTURE ) [ IS ] ( X [ <left paren> <length> <right paren> ] )...
<COBOL bit type> ::=
( PIC | PICTURE ) [ IS ]
( B [ <left paren> <length> <right paren> ] )...
<COBOL numeric type> ::=
( PIC | PICTURE ) [ IS ]
S <COBOL nines specification>
[ USAGE [ IS ] ] DISPLAY SIGN LEADING SEPARATE
<COBOL nines specification> ::=
<COBOL nines> [ V [ <COBOL nines> ] ]
| V <COBOL nines>
<COBOL nines> ::= ( 9 [ <left paren> <length> <right paren> ] )...
<COBOL integer type> ::=
<COBOL computational integer>
| <COBOL binary integer>
<COBOL computational integer> ::=
( PIC | PICTURE ) [ IS ] S<COBOL nines>
[ USAGE [ IS ] ] ( COMP | COMPUTATIONAL )
<COBOL binary integer> ::=
( PIC | PICTURE ) [ IS ] S<COBOL nines>
[ USAGE [ IS ] ] BINARY
<Fortran variable definition> ::=
<Fortran type specification>
<Fortran host identifier>
[ ( <comma> <Fortran host identifier> )... ]
<Fortran type specification> ::=
CHARACTER [ <asterisk> <length> ]
[ CHARACTER SET [ IS ]
<character set specification> ]
| BIT [ <asterisk> <length> ]
| INTEGER
| REAL
| DOUBLE PRECISION
<MUMPS variable definition> ::=
( <MUMPS numeric variable> | <MUMPS character variable> )
<semicolon>
<MUMPS numeric variable> ::=
<MUMPS type specification>
<MUMPS host identifier> [ ( <comma> <MUMPS host identifier> )... ]
<MUMPS type specification> ::=
INT
| DEC
[ <left paren> <precision> [ <comma> <scale> ] <right paren> ]
| REAL
<MUMPS character variable> ::=
VARCHAR <MUMPS host identifier> <MUMPS length specification>
[ ( <comma> <MUMPS host identifier> <MUMPS length specification> )... ]
<MUMPS length specification> ::=
<left paren> <length> <right paren>
<Pascal variable definition> ::=
<Pascal host identifier> [ ( <comma> <Pascal host identifier> )... ] <colon>
<Pascal type specification> <semicolon>
<Pascal type specification> ::=
PACKED ARRAY
<left bracket> 1 <double period> <length> <right bracket>
OF CHAR
[ CHARACTER SET [ IS ]
<character set specification> ]
| PACKED ARRAY
<left bracket> 1 <double period> <length> <right bracket>
OF BIT
| INTEGER
| REAL
| CHAR [ CHARACTER SET
[ IS ] <character set specification> ]
| BIT
<PL/I variable definition> ::=
(DCL | DECLARE)
( <PL/I host identifier>
| <left paren> <PL/I host identifier>
[ ( <comma> <PL/I host identifier> )... ] <right paren> )
<PL/I type specification>
[ <character representation>... ] <semicolon>
<PL/I type specification> ::=
( CHAR | CHARACTER ) [ VARYING ]
<left paren><length><right paren>
[ CHARACTER SET
[ IS ] <character set specification> ]
| BIT [ VARYING ] <left paren><length><right paren>
| <PL/I type fixed decimal> <left paren> <precision>
[ <comma> <scale> ] <right paren>
| <PL/I type fixed binary> [ <left paren> <precision> <right paren> ]
| <PL/I type float binary> <left paren> <precision> <right paren>
<PL/I type fixed decimal> ::=
( DEC | DECIMAL ) FIXED
| FIXED ( DEC | DECIMAL )
<PL/I type fixed binary> ::=
( BIN | BINARY ) FIXED
| FIXED ( BIN | BINARY )
<PL/I type float binary> ::=
( BIN | BINARY ) FLOAT
| FLOAT ( BIN | BINARY )
<embedded SQL end declare> ::=
<SQL prefix> END DECLARE SECTION
[ <SQL terminator> ]
<embedded SQL MUMPS declare> ::=
<SQL prefix>
BEGIN DECLARE SECTION
[ <embedded character set declaration> ]
[ <host variable definition>... ]
END DECLARE SECTION
<SQL terminator>
<embedded SQL statement> ::=
<SQL prefix>
<statement or declaration>
[ <SQL terminator> ]
<statement or declaration> ::=
<declare cursor>
| <dynamic declare cursor>
| <temporary table declaration>
| <embedded exception declaration>
| <SQL procedure statement>
<embedded exception declaration> ::=
WHENEVER <condition> <condition action>
<condition> ::=
SQLERROR | NOT FOUND
<condition action> ::=
CONTINUE | <go to>
<go to> ::=
( GOTO | GO TO ) <goto target>
<goto target> ::=
<host label identifier>
| <unsigned integer>
| <host PL/I label variable>
<host label identifier> ::= !!<EMPHASIS>(See the Syntax Rules.)
<host PL/I label variable> ::= !!<EMPHASIS>(See the Syntax Rules.)
<preparable statement> ::=
<preparable SQL data statement>
| <preparable SQL schema statement>
| <preparable SQL transaction statement>
| <preparable SQL session statement>
| <preparable implementation-defined statement>
<preparable SQL data statement> ::=
<delete statement: searched>
| <dynamic single row select statement>
| <insert statement>
| <dynamic select statement>
| <update statement: searched>
| <preparable dynamic delete statement: positioned>
| <preparable dynamic update statement: positioned>
<dynamic single row select statement> ::= <query specification>
<dynamic select statement> ::= <cursor specification>
<preparable dynamic delete statement: positioned> ::=
DELETE [ FROM <table name> ]
WHERE CURRENT OF <cursor name>
<preparable dynamic update statement: positioned> ::=
UPDATE [ <table name> ]
SET <set clause list>
WHERE CURRENT OF <cursor name>
<preparable SQL schema statement> ::=
<SQL schema statement>
<preparable SQL transaction statement> ::=
<SQL transaction statement>
<preparable SQL session statement> ::=
<SQL session statement>
<preparable implementation-defined statement> ::=
!! <EMPHASIS>(See the Syntax Rules.)
<direct SQL statement> ::=
<directly executable statement> <semicolon>
<directly executable statement> ::=
<direct SQL data statement>
| <SQL schema statement>
| <SQL transaction statement>
| <SQL connection statement>
| <SQL session statement>
| <direct implementation-defined statement>
<direct SQL data statement> ::=
<delete statement: searched>
| <direct select statement: multiple rows>
| <insert statement>
| <update statement: searched>
| <temporary table declaration>
<direct select statement: multiple rows> ::=
<query expression> [ <order by clause> ]
<direct implementation-defined statement> ::=
!!<EMPHASIS>(See the Syntax Rules)
<SQL object identifier> ::=
<SQL provenance> <SQL variant>
<SQL provenance> ::= <arc1> <arc2> <arc3>
<arc1> ::= iso | 1 | iso <left paren> 1 <right paren>
<arc2> ::= standard | 0 | standard <left paren> 0 <right paren>
<arc3> ::= 9075
<SQL variant> ::= <SQL edition> <SQL conformance>
<SQL edition> ::= <1987> | <1989> | <1992>
<1987> ::= 0 | edition1987 <left paren> 0 <right paren>
<1989> ::= <1989 base> <1989 package>
<1989 base> ::= 1 | edition1989 <left paren> 1 <right paren>
<1989 package> ::= <integrity no> | <integrity yes>
<integrity no> ::= 0 | IntegrityNo <left paren> 0 <right paren>
<integrity yes> ::= 1 | IntegrityYes <left paren> 1 <right paren>
<1992> ::= 2 | edition1992 <left paren> 2 <right paren>
<SQL conformance> ::= <low> | <intermediate> | <high>
<low> ::= 0 | Low <left paren> 0 <right paren>
<intermediate> ::= 1 | Intermediate <left paren> 1 <right paren>
<high> ::= 2 | High <left paren> 2 <right paren>
[1mAF. ÐáñÜñôçìá B - Ïäçãüò ÅêìÜèçóçò SQL ãéá áñ÷Üñéïõò[0m
[1mAF.1. Ïäçãüò ÅêìÜèçóçò ãéá PostgreSQL[0m
Ìáæß ìå ôç äéáíïìÞ ôçò PostgreSQL äéáíåßìåôáé ïäçãüò åêìÜèçóçò SQL.
Ôá scripts ôïõ ïäçãïý åêìÜèçóçò SQL âñßóêïíôáé óôïí êáôÜëïãï
src/tutorial
[1mAF.2. Äåßêôåò Internet äéåõèýíóåùí[0m
Ïé áñ÷Üñéïé ìðïñïýí íá âñïõí ïäçãü åêìÜèçóçò SQL óôï
· <http://w3.one.net/~jhoffman/sqltut.htm>
Ó÷üëéá Þ õðïäåßîåéò; Óôåßëôå mail óôï
· jhoffman@one.net
Ôá ðáñáêÜôù sites ðñïôåßíïíôáé áðü ôïí John Hoffman:
· Åã÷åéñßäéï SQL
<http://www.contrib.andrew.cmu.edu/~shadow/sql.html>
· ÅðéêïéíùíÞóôå ìå ôçí SQL Pro
<http://www.inquiry.com/techtips/thesqlpro/>
· ×ñÞóéìá Sites ãéá ôç ó÷åóéáêÞ âÜóç äåäïìÝíùí SQL Pro
<http://www.inquiry.com/techtips/thesqlpro/usefulsites.html>
· Êþäéêáò ãéá ðñïãñáììáôéóôÝò
<http://infoweb.magi.com/~steve/develop.html>
· DBMS Sites <http://info.itu.ch/special/wwwfiles> Ðçãáßíåôå åäþ êáé
äåßôå ôï áñ÷åßï comp_db.html
· DB Ingredients <http://www.compapp.dcu.ie/databases/f017.html>
· Web Authoring <http://www.stars.com/Tutorial/CGI/>
· Computing Dictionary <http://wfn-shop.princeton.edu/cgi-
bin/foldoc>
· DBMS Lab/Links <http://www-ccs.cs.umass.edu/db.html>
· SQL FAQ
<http://epoch.CS.Berkeley.EDU:8000/sequoia/dba/montage/FAQ>
Ðçãáßíåôå åäþ êáé äåßôå ôï áñ÷åßï SQL_TOC.html
· ÂÜóåéò SQL <http://chaos.mur.csu.edu.au/itc125/cgi/sqldb.html>
· RIT Óåëßäá ãéá Ó÷åäéáóìü ÂÜóåùí
<http://www.it.rit.edu/~wjs/IT/199602/icsa720/icsa720postings.html>
· Database Jump Site <http://www.pcslink.com/~ej/dbweb.html>
· ÂïçèÞìáôá ðñïãñáììáôéóìïý óôï Web
<http://www.eng.uc.edu/~jtilley/tutorial.html>
· ÐçãÝò ãéá ÐñïãñáììáôéóôÝò
<http://www.ndev.com/ndc2/support/resources.htp>
· Ëßóôá åñùôÞóåùí <http://ashok.pair.com/sql.htm>
· ÄéÜöïñá IMAGE SQL
<http://jazz.external.hp.com/training/sqltables/main.html>
· Internet Resource List <http://www.eit.com/web/netservices.html>
[1mAG. Appendix C - Ïäçãßåò ãéá ãñÞãïñç åãêáôÜóôáóç Linux[0m
Áí óêïðåýåôå íá ÷ñçóéìïðïéÞóåôå ôç PostgreSQL óå Linux, êáé ÷ñåéÜæåóôå
âïÞèåéá êáôÜ ôçí åãêáôÜóôáóç óôï Linux, åðéóêåöôåßôå ôïõò äåßêôåò ðïõ
èá âñåßôå óôï Appendix. Êáëýðôïõí ôá ðáñáêÜôù èÝìáôá -
· ×áñáêôçñéóôéêÜ ôïõ Linux - Ãéáôß ôï Linux åßíáé êáëýôåñï ãéá
åîõðçñåôçôÞ âÜóåùí äåäïìÝíùí óå óýãêñéóç ìå ôá Windows 95/NT
· Ïäçãßåò ãéá 10ëåðôç ãñÞãïñç åãêáôÜóôáóç Linux
· Ëßóôá áíáëïãéþí Microsoft-Linux
· ÃñÞãïñá âÞìáôá ãéá íá ìåôáãëùôôßóåôå ôïí ðõñÞíá Linux
· Main Site is at <http://members.spree.com/technology/aldev/>
· Mirror site <http://aldev.8m.com>
· Mirror site <http://aldev.webjump.com>
· Mirror site <http://homepages.infoseek.com/~aldev1/index.html>
· Mirror site <http://www3.bcity.com/aldev/>
