Sophie

Sophie

distrib > Mandriva > 2008.1 > x86_64 > by-pkgid > 05cd670d8a02b2b4a0ffb1756f2e8308 > files > 4409

php-manual-zh-5.2.4-1mdv2008.1.noarch.rpm

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>sqlite_create_function</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REL="HOME"
TITLE="PHP 手册"
HREF="index.html"><LINK
REL="UP"
TITLE="SQLite Functions"
HREF="ref.sqlite.html"><LINK
REL="PREVIOUS"
TITLE="sqlite_create_aggregate"
HREF="function.sqlite-create-aggregate.html"><LINK
REL="NEXT"
TITLE="sqlite_current"
HREF="function.sqlite-current.html"><META
HTTP-EQUIV="Content-type"
CONTENT="text/html; charset=UTF-8"></HEAD
><BODY
CLASS="refentry"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>PHP 手册</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="function.sqlite-create-aggregate.html"
ACCESSKEY="P"
>上一页</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="function.sqlite-current.html"
ACCESSKEY="N"
>下一页</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="function.sqlite-create-function"
></A
>sqlite_create_function</H1
><DIV
CLASS="refnamediv"
><A
NAME="AEN216193"
></A
><P
>    (PHP 5)</P
>sqlite_create_function<P
>    (no version information, might be only in CVS)</P
>SQLiteDatabase-&#62;createFunction&nbsp;--&nbsp;
   Registers a "regular" User Defined Function for use in SQL statements
  </DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN216197"
></A
><H2
>说明</H2
>void <B
CLASS="methodname"
>sqlite_create_function</B
> ( resource dbhandle, string function_name, callback callback [, int num_args] )<BR
></BR
><P
>Object oriented style (method):</P
>class <B
CLASS="classname"
>SQLiteDatabase</B
> { <BR
></BR
>void <B
CLASS="methodname"
>createFunction</B
> ( string function_name, callback callback [, int num_args] )<BR
></BR
>}<P
>&#13;   <B
CLASS="function"
>sqlite_create_function()</B
> allows you to register a PHP
   function with SQLite as an <ACRONYM
CLASS="acronym"
>UDF</ACRONYM
> (User Defined
   Function), so that it can be called from within your SQL statements.
  </P
><P
>&#13;   The UDF can be used in any SQL statement that can call functions, such as
   SELECT and UPDATE statements and also in triggers.
  </P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN216234"
></A
><H2
>参数</H2
><P
>&#13;   <P
></P
><DIV
CLASS="variablelist"
><DL
><DT
><CODE
CLASS="parameter"
>dbhandle</CODE
></DT
><DD
><P
>&#13;       The SQLite Database resource; returned from <A
HREF="function.sqlite-open.html"
><B
CLASS="function"
>sqlite_open()</B
></A
>
       when used procedurally.  This parameter is not required
       when using the object-oriented method.
      </P
></DD
><DT
><CODE
CLASS="parameter"
>function_name</CODE
></DT
><DD
><P
>&#13;       The name of the function used in SQL statements.
      </P
></DD
><DT
><CODE
CLASS="parameter"
>callback</CODE
></DT
><DD
><P
>&#13;       Callback function to handle the defined SQL function.
      </P
><DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>注意: </B
>
        Callback functions should return a type understood by SQLite (i.e.
        <A
HREF="language.types.html#language.types.intro"
>scalar type</A
>).
       </P
></BLOCKQUOTE
></DIV
></DD
><DT
><CODE
CLASS="parameter"
>num_args</CODE
></DT
><DD
><P
>&#13;       Hint to the SQLite parser if the callback function accepts a
       predetermined number of arguments.
      </P
></DD
></DL
></DIV
>
  </P
><DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>注意: </B
>为兼容其它数据库(例如
MySQL),支持另两种替代的语法。推荐用第一种,<CODE
CLASS="parameter"
>dbhandle</CODE
>
参数作为函数的第一个参数。</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN216265"
></A
><H2
>返回值</H2
><P
>&#13;   无返回值。
  </P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN216268"
></A
><H2
>范例</H2
><P
>&#13;   <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN216271"
></A
><P
><B
>例 1. <B
CLASS="function"
>sqlite_create_function()</B
> example</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB">&lt;?php<br /></font><font color="#007700">function </font><font color="#0000BB">md5_and_reverse</font><font color="#007700">(</font><font color="#0000BB">$string</font><font color="#007700">) <br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;return </font><font color="#0000BB">strrev</font><font color="#007700">(</font><font color="#0000BB">md5</font><font color="#007700">(</font><font color="#0000BB">$string</font><font color="#007700">));<br />}<br /><br />if (</font><font color="#0000BB">$dbhandle </font><font color="#007700">= </font><font color="#0000BB">sqlite_open</font><font color="#007700">(</font><font color="#DD0000">'mysqlitedb'</font><font color="#007700">, </font><font color="#0000BB">0666</font><font color="#007700">, </font><font color="#0000BB">$sqliteerror</font><font color="#007700">)) {<br />&nbsp;&nbsp;&nbsp;&nbsp;<br />&nbsp;&nbsp;&nbsp;&nbsp;</font><font color="#0000BB">sqlite_create_function</font><font color="#007700">(</font><font color="#0000BB">$dbhandle</font><font color="#007700">, </font><font color="#DD0000">'md5rev'</font><font color="#007700">, </font><font color="#DD0000">'md5_and_reverse'</font><font color="#007700">, </font><font color="#0000BB">1</font><font color="#007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;<br />&nbsp;&nbsp;&nbsp;&nbsp;</font><font color="#0000BB">$sql&nbsp;&nbsp;</font><font color="#007700">= </font><font color="#DD0000">'SELECT md5rev(filename) FROM files'</font><font color="#007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;</font><font color="#0000BB">$rows </font><font color="#007700">= </font><font color="#0000BB">sqlite_array_query</font><font color="#007700">(</font><font color="#0000BB">$dbhandle</font><font color="#007700">, </font><font color="#0000BB">$sql</font><font color="#007700">);<br />} else {<br />&nbsp;&nbsp;&nbsp;&nbsp;echo </font><font color="#DD0000">'Error opening sqlite db: ' </font><font color="#007700">. </font><font color="#0000BB">$sqliteerror</font><font color="#007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;exit;<br />}<br /></font><font color="#0000BB">?&gt;</font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
  </P
><P
>&#13;   In this example, we have a function that calculates the md5 sum of a
   string, and then reverses it.  When the SQL statement executes, it
   returns the value of the filename transformed by our function.  The data
   returned in <CODE
CLASS="parameter"
>$rows</CODE
> contains the processed result.
  </P
><P
>&#13;   The beauty of this technique is that you do not need to process the
   result using a foreach() loop after you have queried for the data.
  </P
><P
>&#13;   PHP registers a special function named <TT
CLASS="literal"
>php</TT
> when the
   database is first opened.  The php function can be used to call any PHP
   function without having to register it first.
  </P
><P
>&#13;   <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN216281"
></A
><P
><B
>例 2. Example of using the PHP function</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB">&lt;?php<br />$rows </font><font color="#007700">= </font><font color="#0000BB">sqlite_array_query</font><font color="#007700">(</font><font color="#0000BB">$dbhandle</font><font color="#007700">, </font><font color="#DD0000">"SELECT php('md5', filename) from files"</font><font color="#007700">);<br /></font><font color="#0000BB">?&gt;</font>
</font>
</code></TD
></TR
></TABLE
><P
>&#13;     This example will call the <A
HREF="function.md5.html"
><B
CLASS="function"
>md5()</B
></A
> on each
     <TT
CLASS="literal"
>filename</TT
> column in the database and return the result
     into <CODE
CLASS="parameter"
>$rows</CODE
>
    </P
></DIV
></TD
></TR
></TABLE
>
  </P
><DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>注意: </B
>
    For performance reasons, PHP will not automatically encode/decode binary
    data passed to and from your UDF's.  You need to manually encode/decode
    the parameters and return values if you need to process binary data in
    this way.  Take a look at <A
HREF="function.sqlite-udf-encode-binary.html"
><B
CLASS="function"
>sqlite_udf_encode_binary()</B
></A
>
    and <A
HREF="function.sqlite-udf-decode-binary.html"
><B
CLASS="function"
>sqlite_udf_decode_binary()</B
></A
> for more details.
   </P
></BLOCKQUOTE
></DIV
><DIV
CLASS="tip"
><BLOCKQUOTE
CLASS="tip"
><P
><B
>提示: </B
>
    It is not recommended to use UDF's to handle processing of
    binary data, unless high performance is not a key requirement of your
    application.
   </P
></BLOCKQUOTE
></DIV
><DIV
CLASS="tip"
><BLOCKQUOTE
CLASS="tip"
><P
><B
>提示: </B
>
    You can use <B
CLASS="function"
>sqlite_create_function()</B
> and
    <A
HREF="function.sqlite-create-aggregate.html"
><B
CLASS="function"
>sqlite_create_aggregate()</B
></A
> to override SQLite native
    SQL functions.
   </P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN216298"
></A
><H2
>参见</H2
><P
>&#13;   <P
></P
><TABLE
BORDER="0"
><TBODY
><TR
><TD
><A
HREF="function.sqlite-create-aggregate.html"
><B
CLASS="function"
>sqlite_create_aggregate()</B
></A
></TD
></TR
></TBODY
></TABLE
><P
></P
>
  </P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="function.sqlite-create-aggregate.html"
ACCESSKEY="P"
>上一页</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>起始页</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="function.sqlite-current.html"
ACCESSKEY="N"
>下一页</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>sqlite_create_aggregate</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="ref.sqlite.html"
ACCESSKEY="U"
>上一级</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>sqlite_current</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>