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><DIV
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><A
NAME="ref.pdo"
></A
><DIV
CLASS="TITLEPAGE"
><H1
CLASS="title"
>CXXII. PDO Functions</H1
><DIV
CLASS="PARTINTRO"
><A
NAME="AEN175436"
></A
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.intro"
>简介</A
></H1
><P
> The PHP Data Objects (PDO) extension defines a lightweight, consistent interface
for accessing databases in PHP. Each database driver that
implements the PDO interface can expose database-specific
features as regular extension functions. Note that you cannot
perform any database functions using the PDO extension by
itself; you must use a <A
HREF="ref.pdo.html#pdo.drivers"
>database-specific
PDO driver</A
> to access a database server.
</P
><P
> PDO provides a <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>data-access</I
></SPAN
> abstraction layer, which
means that, regardless of which database you're using, you use the same
functions to issue queries and fetch data. PDO does
<SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>not</I
></SPAN
> provide a <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>database</I
></SPAN
>
abstraction; it doesn't rewrite SQL or emulate missing features. You
should use a full-blown abstraction layer if you need that facility.
</P
><P
> PDO ships with PHP 5.1, and is available as a PECL extension for PHP 5.0;
PDO requires the new OO features in the core of PHP 5, and so will not
run with earlier versions of PHP.
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.installation"
>安装</A
></H1
><DIV
CLASS="procedure"
><P
><B
><A
NAME="pdo.install.unix51up"
></A
>PHP 5.1 and up on Unix systems</B
></P
><OL
TYPE="1"
><LI
CLASS="step"
><P
> If you're running a PHP 5.1 release, PDO and <A
HREF="ref.pdo-sqlite.html"
>PDO_SQLITE</A
> is included in the distribution;
it will be automatically enabled when you run configure. It is
recommended that you build PDO as a shared extension, as this will allow
you to take advantage of updates that are made available via PECL. The
recommended configure line for building PHP with PDO support should
enable zlib support (for the pecl installer) as well. You may also need
to enable the PDO driver for your database of choice; consult the
documentation for <A
HREF="ref.pdo.html#pdo.drivers"
>database-specific
PDO drivers</A
> to find out more about that, but note that if you
build PDO as a shared extension, you must build the PDO drivers as
shared extensions.
SQLite extension depends on PDO so if PDO is built as a shared extension,
SQLite needs to be built the same way.
<TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="screen"
>./configure --with-zlib --enable-pdo=shared --with-pdo-sqlite=shared --with-sqlite=shared</PRE
></TD
></TR
></TABLE
>
</P
></LI
><LI
CLASS="step"
><P
> After installing PDO as a shared module, you must edit your php.ini file
so that the PDO extension will be loaded automatically when PHP runs.
You will also need to enable any database specific drivers there too;
make sure that they are listed after the pdo.so line, as PDO must be
initialized before the database-specific extensions can be loaded.
If you built PDO and the database-specific extensions statically, you
can skip this step.
<TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="screen"
>extension=pdo.so</PRE
></TD
></TR
></TABLE
>
</P
></LI
><LI
CLASS="step"
><P
> Having PDO as a shared module will allow you to run <B
CLASS="command"
>pecl
upgrade pdo</B
> as new versions of PDO are published, without
forcing you to rebuild the whole of PHP. Note that if you do this, you
also need to upgrade your database specific PDO drivers at the same
time.
</P
></LI
></OL
></DIV
><DIV
CLASS="procedure"
><P
><B
><A
NAME="pdo.install.pecl"
></A
>PHP 5.0.0 and up on Unix systems</B
></P
><OL
TYPE="1"
><LI
CLASS="step"
><P
> PDO is available as a PECL extension from
<A
HREF="http://pecl.php.net/package/pdo"
TARGET="_top"
>http://pecl.php.net/package/pdo</A
>.
Installation can be performed via the <B
CLASS="command"
>pecl</B
> tool; this
is enabled by default when you configure PHP. You should ensure that
PHP was configured --with-zlib in order for
<B
CLASS="command"
>pecl</B
> to be able to handle the compressed package
files.
</P
></LI
><LI
CLASS="step"
><P
> Run the following command to download, build, and install the
latest stable version of PDO:
<TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="screen"
>pecl install pdo</PRE
></TD
></TR
></TABLE
>
</P
></LI
><LI
CLASS="step"
><P
> The <B
CLASS="command"
>pecl</B
> command automatically installs the
PDO module into your PHP extensions directory. To enable the
PDO extension on Linux or Unix operating systems, you must add
the following line to <TT
CLASS="filename"
>php.ini</TT
>:
<TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="screen"
>extension=pdo.so</PRE
></TD
></TR
></TABLE
>
</P
><P
> For more information about building PECL packages, consult the
<A
HREF="install.pecl.html"
>PECL installation</A
> section of the manual.
</P
></LI
></OL
></DIV
><DIV
CLASS="procedure"
><P
><B
><A
NAME="pdo.install.win32php51"
></A
>Windows users running PHP 5.1.0 and up</B
></P
><OL
TYPE="1"
><LI
CLASS="step"
><P
> PDO and all the major drivers ship with PHP as shared extensions, and
simply need to be activated by editing the <TT
CLASS="filename"
>php.ini</TT
> file:
<TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="screen"
>extension=php_pdo.dll</PRE
></TD
></TR
></TABLE
>
</P
></LI
><LI
CLASS="step"
><P
> Next, choose the other database-specific DLL files and either use
<A
HREF="function.dl.html"
><B
CLASS="function"
>dl()</B
></A
> to load them at runtime, or enable them in
<TT
CLASS="filename"
>php.ini</TT
> below <TT
CLASS="filename"
>php_pdo.dll</TT
>. For example:
<TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="screen"
>extension=php_pdo.dll
extension=php_pdo_firebird.dll
extension=php_pdo_informix.dll
extension=php_pdo_mssql.dll
extension=php_pdo_mysql.dll
extension=php_pdo_oci.dll
extension=php_pdo_oci8.dll
extension=php_pdo_odbc.dll
extension=php_pdo_pgsql.dll
extension=php_pdo_sqlite.dll</PRE
></TD
></TR
></TABLE
>
</P
><P
> These DLLs should exist in the system's
<A
HREF="ini.core.html#ini.extension-dir"
>extension_dir</A
>.
Note that <A
HREF="ref.pdo-informix.html"
>PDO_INFORMIX</A
>
is only available as a PECL extension.
</P
></LI
></OL
></DIV
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.configuration"
>运行时配置</A
></H1
><P
>这些函数的行为受 <TT
CLASS="filename"
>php.ini</TT
> 的影响。</P
><P
> <DIV
CLASS="table"
><A
NAME="AEN175498"
></A
><P
><B
>表 1. PDO Configuration Options</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><COL><COL><THEAD
><TR
><TH
>Name</TH
><TH
>Default</TH
><TH
>Changeable</TH
><TH
>Changelog</TH
></TR
></THEAD
><TBODY
><TR
><TD
>pdo.dsn.*</TD
><TD
> </TD
><TD
><TT
CLASS="filename"
>php.ini</TT
> only</TD
><TD
> </TD
></TR
></TBODY
></TABLE
></DIV
>
有关 PHP_INI_* 常量进一步的细节与定义参见<A
HREF="ini.html"
>附录 H</A
>。
</P
><P
>以下是配置选项的简要解释。</P
><P
> <P
></P
><DIV
CLASS="variablelist"
><DL
><DT
><A
NAME="ini.pdo.dsn"
></A
><CODE
CLASS="parameter"
>pdo.dsn.*</CODE
>
<A
HREF="language.types.string.html"
><B
CLASS="type"
>string</B
></A
></DT
><DD
><P
> Defines DSN alias. See <A
HREF="function.pdo-construct.html"
>PDO->__construct()</A
> for
thorough explanation.
</P
></DD
></DL
></DIV
>
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.drivers"
>PDO Drivers</A
></H1
><P
> The following drivers currently implement the PDO interface:
<DIV
CLASS="informaltable"
><P
></P
><A
NAME="AEN175528"
></A
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><THEAD
><TR
><TH
>Driver name</TH
><TH
>Supported databases</TH
></TR
></THEAD
><TBODY
><TR
><TD
><A
HREF="ref.pdo-dblib.html"
>PDO_DBLIB</A
></TD
><TD
>FreeTDS / Microsoft SQL Server / Sybase</TD
></TR
><TR
><TD
><A
HREF="ref.pdo-firebird.html"
>PDO_FIREBIRD</A
></TD
><TD
>Firebird/Interbase 6</TD
></TR
><TR
><TD
><A
HREF="ref.pdo-ibm.html"
>PDO_IBM</A
></TD
><TD
>IBM DB2</TD
></TR
><TR
><TD
><A
HREF="ref.pdo-informix.html"
>PDO_INFORMIX</A
></TD
><TD
>IBM Informix Dynamic Server</TD
></TR
><TR
><TD
><A
HREF="ref.pdo-mysql.html"
>PDO_MYSQL</A
></TD
><TD
>MySQL 3.x/4.x/5.x</TD
></TR
><TR
><TD
><A
HREF="ref.pdo-oci.html"
>PDO_OCI</A
></TD
><TD
>Oracle Call Interface</TD
></TR
><TR
><TD
><A
HREF="ref.pdo-odbc.html"
>PDO_ODBC</A
></TD
><TD
>ODBC v3 (IBM DB2, unixODBC and win32 ODBC)</TD
></TR
><TR
><TD
><A
HREF="ref.pdo-pgsql.html"
>PDO_PGSQL</A
></TD
><TD
>PostgreSQL</TD
></TR
><TR
><TD
><A
HREF="ref.pdo-sqlite.html"
>PDO_SQLITE</A
></TD
><TD
>SQLite 3 and SQLite 2</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
>
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.connections"
>Connections and Connection management</A
></H1
><P
> Connections are established by creating instances of the PDO base class.
It doesn't matter which driver you want to use; you always use the PDO
class name. The constructor accepts parameters for specifying the
database source (known as the DSN) and optionally for the username and
password (if any).
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175575"
></A
><P
><B
>例 1. Connecting to MySQL</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$dbh </font><font color="#007700">= new </font><font color="#0000BB">PDO</font><font color="#007700">(</font><font color="#DD0000">'mysql:host=localhost;dbname=test'</font><font color="#007700">, </font><font color="#0000BB">$user</font><font color="#007700">, </font><font color="#0000BB">$pass</font><font color="#007700">);<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> If there are any connection errors, a <TT
CLASS="literal"
>PDOException</TT
>
object will be thrown. You may catch the exception if you want to handle
the error condition, or you may opt to leave it for an application
global exception handler that you set up via
<A
HREF="function.set-exception-handler.html"
><B
CLASS="function"
>set_exception_handler()</B
></A
>.
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175582"
></A
><P
><B
>例 2. Handling connection errors</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />try </font><font color="#007700">{<br /> </font><font color="#0000BB">$dbh </font><font color="#007700">= new </font><font color="#0000BB">PDO</font><font color="#007700">(</font><font color="#DD0000">'mysql:host=localhost;dbname=test'</font><font color="#007700">, </font><font color="#0000BB">$user</font><font color="#007700">, </font><font color="#0000BB">$pass</font><font color="#007700">);<br /> foreach (</font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">query</font><font color="#007700">(</font><font color="#DD0000">'SELECT * from FOO'</font><font color="#007700">) as </font><font color="#0000BB">$row</font><font color="#007700">) {<br /> </font><font color="#0000BB">print_r</font><font color="#007700">(</font><font color="#0000BB">$row</font><font color="#007700">);<br /> }<br /> </font><font color="#0000BB">$dbh </font><font color="#007700">= </font><font color="#0000BB">null</font><font color="#007700">;<br />} </font><font color="#0000BB">catch </font><font color="#007700">(</font><font color="#0000BB">PDOException $e</font><font color="#007700">) {<br /> print </font><font color="#DD0000">"Error!: " </font><font color="#007700">. </font><font color="#0000BB">$e</font><font color="#007700">-></font><font color="#0000BB">getMessage</font><font color="#007700">() . </font><font color="#DD0000">"<br/>"</font><font color="#007700">;<br /> die();<br />}<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><DIV
CLASS="warning"
><P
></P
><TABLE
CLASS="warning"
BORDER="1"
WIDTH="100%"
><TR
><TD
ALIGN="CENTER"
><B
>警告</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
> If your application does not catch the exception thrown from the PDO
constructor, the default action taken by the zend engine is to terminate
the script and display a back trace. This back trace will likely reveal
the full database connection details, including the username and
password. It is your responsibility to catch this exception, either
explicitly (via a <TT
CLASS="literal"
>catch</TT
> statement) or implicitly via
<A
HREF="function.set-exception-handler.html"
><B
CLASS="function"
>set_exception_handler()</B
></A
>.
</P
></TD
></TR
></TABLE
></DIV
><P
> Upon successful connection to the database, an instance of the PDO class
is returned to your script. The connection remains active for the
lifetime of that PDO object. To close the connection, you need to
destroy the object by ensuring that all remaining references to it are
deleted--you do this by assigning <TT
CLASS="constant"
><B
>NULL</B
></TT
> to the variable that holds the
object. If you don't do this explicitly, PHP will automatically close
the connection when your script ends.
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175592"
></A
><P
><B
>例 3. Closing a connection</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$dbh </font><font color="#007700">= new </font><font color="#0000BB">PDO</font><font color="#007700">(</font><font color="#DD0000">'mysql:host=localhost;dbname=test'</font><font color="#007700">, </font><font color="#0000BB">$user</font><font color="#007700">, </font><font color="#0000BB">$pass</font><font color="#007700">);<br /></font><font color="#FF8000">// use the connection here<br /><br /><br />// and now we're done; close it<br /></font><font color="#0000BB">$dbh </font><font color="#007700">= </font><font color="#0000BB">null</font><font color="#007700">;<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> Many web applications will benefit from making persistent connections to
database servers. Persistent connections are not closed at the end of the
script, but are cached and re-used when another script requests a
connection using the same credentials. The persistent connection cache
allows you to avoid the overhead of establishing a new connection every
time a script needs to talk to a database, resulting in a faster web
application.
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175597"
></A
><P
><B
>例 4. Persistent connections</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$dbh </font><font color="#007700">= new </font><font color="#0000BB">PDO</font><font color="#007700">(</font><font color="#DD0000">'mysql:host=localhost;dbname=test'</font><font color="#007700">, </font><font color="#0000BB">$user</font><font color="#007700">, </font><font color="#0000BB">$pass</font><font color="#007700">, array(<br /> </font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">ATTR_PERSISTENT </font><font color="#007700">=> </font><font color="#0000BB">true<br /></font><font color="#007700">));<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>注意: </B
>
If you're using the PDO ODBC driver and your ODBC libraries support ODBC
Connection Pooling (unixODBC and Windows are two that do; there may be
more), then it's recommended that you don't use persistent PDO
connections, and instead leave the connection caching to the ODBC
Connection Pooling layer. The ODBC Connection Pool is shared with other
modules in the process; if PDO is told to cache the connection, then
that connection would never be returned to the ODBC connection pool,
resulting in additional connections being created to service those other
modules.
</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.transactions"
>Transactions and auto-commit</A
></H1
><P
> Now that you're connected via PDO, you must understand how PDO
manages transactions before you start issuing queries. If you've never
encountered transactions before, they offer 4 major features: Atomicity,
Consistency, Isolation and Durability (ACID). In layman's terms, any work
carried out in a transaction, even if it is carried out in stages, is
guaranteed to be applied to the database safely, and without interference
from other connections, when it is committed. Transactional work can also
be automatically undone at your request (provided you haven't already
committed it), which makes error handling in your scripts easier.
</P
><P
> Transactions are typically implemented by "saving-up" your batch of
changes to be applied all at once; this has the nice side effect of
drastically improving the efficiency of those updates. In other words,
transactions can make your scripts faster and potentially more robust
(you still need to use them correctly to reap that benefit).
</P
><P
> Unfortunately, not every database supports transactions, so PDO needs to
run in what is known as "auto-commit" mode when you first open the
connection. Auto-commit mode means that every query that you run has its
own implicit transaction, if the database supports it, or no transaction
if the database doesn't support transactions. If you need a transaction,
you must use the <A
HREF="function.pdo-begintransaction.html"
>PDO->beginTransaction()</A
> method to
initiate one. If the underlying driver does not support transactions, a
PDOException will be thrown (regardless of your error handling settings:
this is always a serious error condition). Once you are in a transaction,
you may use <A
HREF="function.pdo-commit.html"
>PDO->commit()</A
> or
<A
HREF="function.pdo-rollback.html"
>PDO->rollBack()</A
> to finish it, depending on the success
of the code you run during the transaction.
</P
><P
> When the script ends or when a connection is about to be closed, if you
have an outstanding transaction, PDO will automatically roll it back.
This is a safety measure to help avoid inconsistency in the cases where
the script terminates unexpectedly--if you didn't explicitly commit the
transaction, then it is assumed that something went awry, so the rollback
is performed for the safety of your data.
</P
><DIV
CLASS="warning"
><P
></P
><TABLE
CLASS="warning"
BORDER="1"
WIDTH="100%"
><TR
><TD
ALIGN="CENTER"
><B
>警告</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
> The automatic rollback only happens if you initiate the transaction via
<A
HREF="function.pdo-begintransaction.html"
>PDO->beginTransaction()</A
>. If you manually issue a
query that begins a transaction PDO has no way of knowing about it and
thus cannot roll it back if something bad happens.
</P
></TD
></TR
></TABLE
></DIV
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175615"
></A
><P
><B
>例 5. Executing a batch in a transaction</B
></P
><P
> In the following sample, let's assume that we are creating a set of
entries for a new employee, who has been assigned an ID number of 23.
In addition to entering the basic data for that person, we also need to
record their salary. It's pretty simple to make two separate updates,
but by enclosing them within the
<A
HREF="function.pdo-begintransaction.html"
>PDO->beginTransaction()</A
> and
<A
HREF="function.pdo-commit.html"
>PDO->commit()</A
> calls, we are guaranteeing that no one
else will be able to see those changes until they are complete. If
something goes wrong, the catch block rolls back all changes made
since the transaction was started, and then prints out an error
message.
</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />try </font><font color="#007700">{<br /> </font><font color="#0000BB">$dbh </font><font color="#007700">= new </font><font color="#0000BB">PDO</font><font color="#007700">(</font><font color="#DD0000">'odbc:SAMPLE'</font><font color="#007700">, </font><font color="#DD0000">'db2inst1'</font><font color="#007700">, </font><font color="#DD0000">'ibmdb2'</font><font color="#007700">, <br /> array(</font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">ATTR_PERSISTENT </font><font color="#007700">=> </font><font color="#0000BB">true</font><font color="#007700">));<br /> echo </font><font color="#DD0000">"Connected\n"</font><font color="#007700">;<br /> </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">setAttribute</font><font color="#007700">(</font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">ATTR_ERRMODE</font><font color="#007700">, </font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">ERRMODE_EXCEPTION</font><font color="#007700">);<br /><br /> </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">beginTransaction</font><font color="#007700">();<br /> </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">exec</font><font color="#007700">(</font><font color="#DD0000">"insert into staff (id, first, last) values (23, 'Joe', 'Bloggs')"</font><font color="#007700">);<br /> </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">exec</font><font color="#007700">(</font><font color="#DD0000">"insert into salarychange (id, amount, changedate) <br /> values (23, 50000, NOW())"</font><font color="#007700">);<br /> </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">commit</font><font color="#007700">();<br /> <br />} </font><font color="#0000BB">catch </font><font color="#007700">(</font><font color="#0000BB">Exception $e</font><font color="#007700">) {<br /> </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">rollBack</font><font color="#007700">();<br /> echo </font><font color="#DD0000">"Failed: " </font><font color="#007700">. </font><font color="#0000BB">$e</font><font color="#007700">-></font><font color="#0000BB">getMessage</font><font color="#007700">();<br />}<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> You're not limited to making updates in a transaction; you can also issue
complex queries to extract data, and possibly use that information to
build up more updates and queries; while the transaction is active, you
are guaranteed that no one else can make changes while you are in the
middle of your work. In truth, this isn't 100% correct, but it is a
good-enough introduction, if you've never heard of transactions before.
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.prepared-statements"
>Prepared statements and stored procedures</A
></H1
><P
> Many of the more mature databases support the concept of prepared
statements. What are they? You can think of them as a kind of compiled
template for the SQL that you want to run, that can be customized using
variable parameters. Prepared statements offer two major benefits:
</P
><P
></P
><UL
><LI
><P
> The query only needs to be parsed (or prepared) once, but can be
executed multiple times with the same or different parameters. When the
query is prepared, the database will analyze, compile and optimize it's
plan for executing the query. For complex queries this process can take
up enough time that it will noticeably slow down your application if you
need to repeat the same query many times with different parameters. By
using a prepared statement you avoid repeating the
analyze/compile/optimize cycle. In short, prepared statements use fewer
resources and thus run faster.
</P
></LI
><LI
><P
> The parameters to prepared statements don't need to be quoted; the
driver handles it for you. If your application exclusively uses
prepared statements, you can be sure that no SQL injection will occur.
(However, if you're still building up other parts of the query based on
untrusted input, you're still at risk).
</P
></LI
></UL
><P
> Prepared statements are so useful that they are the only feature that PDO
will emulate for drivers that don't support them. This ensures that you
will be able to use the same data access paradigm regardless of the
capabilities of the database.
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175632"
></A
><P
><B
>例 6. Repeated inserts using prepared statements</B
></P
><P
> This example performs an INSERT query by substituting a <TT
CLASS="literal"
>name</TT
>
and a <TT
CLASS="literal"
>value</TT
> for the named placeholders.
</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$stmt </font><font color="#007700">= </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"INSERT INTO REGISTRY (name, value) VALUES (:name, :value)"</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#DD0000">':name'</font><font color="#007700">, </font><font color="#0000BB">$name</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#DD0000">':value'</font><font color="#007700">, </font><font color="#0000BB">$value</font><font color="#007700">);<br /><br /></font><font color="#FF8000">// insert one row<br /></font><font color="#0000BB">$name </font><font color="#007700">= </font><font color="#DD0000">'one'</font><font color="#007700">;<br /></font><font color="#0000BB">$value </font><font color="#007700">= </font><font color="#0000BB">1</font><font color="#007700">;<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">();<br /><br /></font><font color="#FF8000">// insert another row with different values<br /></font><font color="#0000BB">$name </font><font color="#007700">= </font><font color="#DD0000">'two'</font><font color="#007700">;<br /></font><font color="#0000BB">$value </font><font color="#007700">= </font><font color="#0000BB">2</font><font color="#007700">;<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">();<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175639"
></A
><P
><B
>例 7. Repeated inserts using prepared statements</B
></P
><P
> This example performs an INSERT query by substituting a <TT
CLASS="literal"
>name</TT
>
and a <TT
CLASS="literal"
>value</TT
> for the positional <TT
CLASS="literal"
>?</TT
> placeholders.
</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$stmt </font><font color="#007700">= </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"INSERT INTO REGISTRY (name, value) VALUES (?, ?)"</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">1</font><font color="#007700">, </font><font color="#0000BB">$name</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">2</font><font color="#007700">, </font><font color="#0000BB">$value</font><font color="#007700">);<br /><br /></font><font color="#FF8000">// insert one row<br /></font><font color="#0000BB">$name </font><font color="#007700">= </font><font color="#DD0000">'one'</font><font color="#007700">;<br /></font><font color="#0000BB">$value </font><font color="#007700">= </font><font color="#0000BB">1</font><font color="#007700">;<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">();<br /><br /></font><font color="#FF8000">// insert another row with different values<br /></font><font color="#0000BB">$name </font><font color="#007700">= </font><font color="#DD0000">'two'</font><font color="#007700">;<br /></font><font color="#0000BB">$value </font><font color="#007700">= </font><font color="#0000BB">2</font><font color="#007700">;<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">();<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175647"
></A
><P
><B
>例 8. Fetching data using prepared statements</B
></P
><P
> This example fetches data based on a key value supplied by a form.
The user input is automatically quoted, so there is no risk of a
SQL injection attack.
</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$stmt </font><font color="#007700">= </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"SELECT * FROM REGISTRY where name = ?"</font><font color="#007700">);<br />if (</font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">(array(</font><font color="#0000BB">$_GET</font><font color="#007700">[</font><font color="#DD0000">'name'</font><font color="#007700">]))) {<br /> while (</font><font color="#0000BB">$row </font><font color="#007700">= </font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">fetch</font><font color="#007700">()) {<br /> </font><font color="#0000BB">print_r</font><font color="#007700">(</font><font color="#0000BB">$row</font><font color="#007700">);<br /> }<br />}<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> If the database driver supports it, you may also bind parameters for
output as well as input. Output parameters are typically used to retrieve
values from stored procedures. Output parameters are slightly more complex
to use than input parameters, in that you must know how large a given
parameter might be when you bind it. If the value turns out to be larger
than the size you suggested, an error is raised.
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175653"
></A
><P
><B
>例 9. Calling a stored procedure with an output parameter</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$stmt </font><font color="#007700">= </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"CALL sp_returns_string(?)"</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">1</font><font color="#007700">, </font><font color="#0000BB">$return_value</font><font color="#007700">, </font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">PARAM_STR</font><font color="#007700">, </font><font color="#0000BB">4000</font><font color="#007700">); <br /><br /></font><font color="#FF8000">// call the stored procedure<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">();<br /><br />print </font><font color="#DD0000">"procedure returned $return_value</font><font color="#007700">\n</font><font color="#DD0000">"</font><font color="#007700">;<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> You may also specify parameters that hold values both input and output;
the syntax is similar to output parameters. In this next example, the
string 'hello' is passed into the stored procedure, and when it returns,
hello is replaced with the return value of the procedure.
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175658"
></A
><P
><B
>例 10. Calling a stored procedure with an input/output parameter</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$stmt </font><font color="#007700">= </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"CALL sp_takes_string_returns_string(?)"</font><font color="#007700">);<br /></font><font color="#0000BB">$value </font><font color="#007700">= </font><font color="#DD0000">'hello'</font><font color="#007700">;<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">1</font><font color="#007700">, </font><font color="#0000BB">$value</font><font color="#007700">, </font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">PARAM_STR</font><font color="#007700">|</font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">PARAM_INPUT_OUTPUT</font><font color="#007700">, </font><font color="#0000BB">4000</font><font color="#007700">); <br /><br /></font><font color="#FF8000">// call the stored procedure<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">();<br /><br />print </font><font color="#DD0000">"procedure returned $value</font><font color="#007700">\n</font><font color="#DD0000">"</font><font color="#007700">;<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175662"
></A
><P
><B
>例 11. Invalid use of placeholder</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$stmt </font><font color="#007700">= </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"SELECT * FROM REGISTRY where name LIKE '%?%'"</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">(array(</font><font color="#0000BB">$_GET</font><font color="#007700">[</font><font color="#DD0000">'name'</font><font color="#007700">]));<br /><br /></font><font color="#FF8000">// placeholder must be used in the place of the whole value<br /></font><font color="#0000BB">$stmt </font><font color="#007700">= </font><font color="#0000BB">$dbh</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"SELECT * FROM REGISTRY where name LIKE ?"</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">(array(</font><font color="#DD0000">"%$_GET</font><font color="#007700">[</font><font color="#DD0000">name</font><font color="#007700">]</font><font color="#DD0000">%"</font><font color="#007700">));<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.error-handling"
>Errors and error handling</A
></H1
><P
> PDO offers you a choice of 3 different error handling strategies, to fit
your style of application development.
</P
><P
></P
><UL
><LI
><P
> <TT
CLASS="constant"
><B
>PDO::ERRMODE_SILENT</B
></TT
>
</P
><P
> This is the default mode. PDO will simply set the error code for you
to inspect using the <A
HREF="function.pdo-errorcode.html"
>PDO->errorCode()</A
> and
<A
HREF="function.pdo-errorinfo.html"
>PDO->errorInfo()</A
> methods on both the
statement and database objects; if the error resulted from a call on a
statement object, you would invoke the
<A
HREF="function.pdostatement-errorcode.html"
>PDOStatement->errorCode()</A
> or
<A
HREF="function.pdostatement-errorinfo.html"
>PDOStatement->errorInfo()</A
>
method on that object. If the error resulted from a call on the
database object, you would invoke those methods on the database object
instead.
</P
></LI
><LI
><P
> <TT
CLASS="constant"
><B
>PDO::ERRMODE_WARNING</B
></TT
>
</P
><P
> In addition to setting the error code, PDO will emit a traditional
E_WARNING message. This setting is useful during debugging/testing, if
you just want to see what problems occurred without interrupting the
flow of the application.
</P
></LI
><LI
><P
> <TT
CLASS="constant"
><B
>PDO::ERRMODE_EXCEPTION</B
></TT
>
</P
><P
> In addition to setting the error code, PDO will throw a
<B
CLASS="classname"
>PDOException</B
>
and set its properties to reflect the error code and error
information. This setting is also useful during debugging, as it will
effectively "blow up" the script at the point of the error, very
quickly pointing a finger at potential problem areas in your code
(remember: transactions are automatically rolled back if the exception
causes the script to terminate).
</P
><P
> Exception mode is also useful because you can structure your error
handling more clearly than with traditional PHP-style warnings, and
with less code/nesting than by running in silent mode and explicitly
checking the return value of each database call.
</P
><P
> See <A
HREF="language.exceptions.html"
>Exceptions</A
> for more
information about Exceptions in PHP.
</P
></LI
></UL
><P
> PDO standardizes on using SQL-92 SQLSTATE error code strings; individual
PDO drivers are responsible for mapping their native codes to the
appropriate SQLSTATE codes. The <A
HREF="function.pdo-errorcode.html"
>PDO->errorCode()</A
>
method returns a single SQLSTATE code. If you need more specific
information about an error, PDO also offers an
<A
HREF="function.pdo-errorinfo.html"
>PDO->errorInfo()</A
> method which returns an array
containing the SQLSTATE code, the driver specific error code and driver
specific error string.
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.lobs"
>Large Objects (LOBs)</A
></H1
><P
> At some point in your application, you might find that you need to store
"large" data in your database. Large typically means "around 4kb or
more", although some databases can happily handle up to 32kb before data becomes
"large". Large objects can be either textual or binary in nature. PDO
allows you to work with this large data type by using the
<TT
CLASS="constant"
><B
>PDO::PARAM_LOB</B
></TT
>
type code in your <A
HREF="function.pdostatement-bindparam.html"
>PDOStatement->bindParam()</A
> or
<A
HREF="function.pdostatement-bindcolumn.html"
>PDOStatement->bindColumn()</A
> calls.
<TT
CLASS="constant"
><B
>PDO::PARAM_LOB</B
></TT
> tells
PDO to map the data as a stream, so that you can manipulate it using the
<A
HREF="ref.stream.html"
>PHP Streams API</A
>.
</P
><P
>
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175702"
></A
><P
><B
>例 12. Displaying an image from a database</B
></P
><P
> This example binds the LOB into the variable named $lob and then sends
it to the browser using <A
HREF="function.fpassthru.html"
><B
CLASS="function"
>fpassthru()</B
></A
>. Since the LOB
is represented as a stream, functions such as
<A
HREF="function.fgets.html"
><B
CLASS="function"
>fgets()</B
></A
>, <A
HREF="function.fread.html"
><B
CLASS="function"
>fread()</B
></A
> and
<A
HREF="function.stream-get-contents.html"
><B
CLASS="function"
>stream_get_contents()</B
></A
> can be used on it.
</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$db </font><font color="#007700">= new </font><font color="#0000BB">PDO</font><font color="#007700">(</font><font color="#DD0000">'odbc:SAMPLE'</font><font color="#007700">, </font><font color="#DD0000">'db2inst1'</font><font color="#007700">, </font><font color="#DD0000">'ibmdb2'</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt </font><font color="#007700">= </font><font color="#0000BB">$db</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"select contenttype, imagedata from images where id=?"</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">(array(</font><font color="#0000BB">$_GET</font><font color="#007700">[</font><font color="#DD0000">'id'</font><font color="#007700">]));<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindColumn</font><font color="#007700">(</font><font color="#0000BB">1</font><font color="#007700">, </font><font color="#0000BB">$type</font><font color="#007700">, </font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">PARAM_STR</font><font color="#007700">, </font><font color="#0000BB">256</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindColumn</font><font color="#007700">(</font><font color="#0000BB">2</font><font color="#007700">, </font><font color="#0000BB">$lob</font><font color="#007700">, </font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">PARAM_LOB</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">fetch</font><font color="#007700">(</font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">FETCH_BOUND</font><font color="#007700">);<br /><br /></font><font color="#0000BB">header</font><font color="#007700">(</font><font color="#DD0000">"Content-Type: $type"</font><font color="#007700">);<br /></font><font color="#0000BB">fpassthru</font><font color="#007700">(</font><font color="#0000BB">$lob</font><font color="#007700">);<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175711"
></A
><P
><B
>例 13. Inserting an image into a database</B
></P
><P
> This example opens up a file and passes the file handle to PDO to insert
it as a LOB. PDO will do its best to get the contents of the file up
to the database in the most efficient manner possible.
</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$db </font><font color="#007700">= new </font><font color="#0000BB">PDO</font><font color="#007700">(</font><font color="#DD0000">'odbc:SAMPLE'</font><font color="#007700">, </font><font color="#DD0000">'db2inst1'</font><font color="#007700">, </font><font color="#DD0000">'ibmdb2'</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt </font><font color="#007700">= </font><font color="#0000BB">$db</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"insert into images (id, contenttype, imagedata) values (?, ?, ?)"</font><font color="#007700">);<br /></font><font color="#0000BB">$id </font><font color="#007700">= </font><font color="#0000BB">get_new_id</font><font color="#007700">(); </font><font color="#FF8000">// some function to allocate a new ID<br /><br />// assume that we are running as part of a file upload form<br />// You can find more information in the PHP documentation<br /><br /></font><font color="#0000BB">$fp </font><font color="#007700">= </font><font color="#0000BB">fopen</font><font color="#007700">(</font><font color="#0000BB">$_FILES</font><font color="#007700">[</font><font color="#DD0000">'file'</font><font color="#007700">][</font><font color="#DD0000">'tmp_name'</font><font color="#007700">], </font><font color="#DD0000">'rb'</font><font color="#007700">);<br /><br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">1</font><font color="#007700">, </font><font color="#0000BB">$id</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">2</font><font color="#007700">, </font><font color="#0000BB">$_FILES</font><font color="#007700">[</font><font color="#DD0000">'file'</font><font color="#007700">][</font><font color="#DD0000">'type'</font><font color="#007700">]);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">3</font><font color="#007700">, </font><font color="#0000BB">$fp</font><font color="#007700">, </font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">PARAM_LOB</font><font color="#007700">);<br /><br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">beginTransaction</font><font color="#007700">();<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">();<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">commit</font><font color="#007700">();<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175716"
></A
><P
><B
>例 14. Inserting an image into a database: Oracle</B
></P
><P
> Oracle requires a slightly different syntax for inserting a lob from a
file. It's also essential that you perform the insert under a
transaction, otherwise your newly inserted LOB will be committed with a
zero-length as part of the implicit commit that happens when the query
is executed:
</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$db </font><font color="#007700">= new </font><font color="#0000BB">PDO</font><font color="#007700">(</font><font color="#DD0000">'oci:'</font><font color="#007700">, </font><font color="#DD0000">'scott'</font><font color="#007700">, </font><font color="#DD0000">'tiger'</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt </font><font color="#007700">= </font><font color="#0000BB">$db</font><font color="#007700">-></font><font color="#0000BB">prepare</font><font color="#007700">(</font><font color="#DD0000">"insert into images (id, contenttype, imagedata) " </font><font color="#007700">.<br /> </font><font color="#DD0000">"VALUES (?, ?, EMPTY_BLOB()) RETURNING imagedata INTO ?"</font><font color="#007700">);<br /></font><font color="#0000BB">$id </font><font color="#007700">= </font><font color="#0000BB">get_new_id</font><font color="#007700">(); </font><font color="#FF8000">// some function to allocate a new ID<br /><br />// assume that we are running as part of a file upload form<br />// You can find more information in the PHP documentation<br /><br /></font><font color="#0000BB">$fp </font><font color="#007700">= </font><font color="#0000BB">fopen</font><font color="#007700">(</font><font color="#0000BB">$_FILES</font><font color="#007700">[</font><font color="#DD0000">'file'</font><font color="#007700">][</font><font color="#DD0000">'tmp_name'</font><font color="#007700">], </font><font color="#DD0000">'rb'</font><font color="#007700">);<br /><br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">1</font><font color="#007700">, </font><font color="#0000BB">$id</font><font color="#007700">);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">2</font><font color="#007700">, </font><font color="#0000BB">$_FILES</font><font color="#007700">[</font><font color="#DD0000">'file'</font><font color="#007700">][</font><font color="#DD0000">'type'</font><font color="#007700">]);<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">bindParam</font><font color="#007700">(</font><font color="#0000BB">3</font><font color="#007700">, </font><font color="#0000BB">$fp</font><font color="#007700">, </font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">PARAM_LOB</font><font color="#007700">);<br /><br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">beginTransaction</font><font color="#007700">();<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">execute</font><font color="#007700">();<br /></font><font color="#0000BB">$stmt</font><font color="#007700">-></font><font color="#0000BB">commit</font><font color="#007700">();<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.classes"
>预定义类</A
></H1
><DIV
CLASS="section"
><H2
CLASS="section"
><A
NAME="pdo.class.PDO"
><B
CLASS="classname"
>PDO</B
></A
></H2
><P
> Represents a connection between PHP and a database server.
</P
><DIV
CLASS="section"
><H3
CLASS="section"
><A
NAME="pdo.class.PDO.constructor"
>构造函数</A
></H3
><P
></P
><UL
><LI
><P
> <A
HREF="function.pdo-construct.html"
>PDO</A
> - constructs a new
PDO object
</P
></LI
></UL
></DIV
><DIV
CLASS="section"
><H3
CLASS="section"
><A
NAME="pdo.class.PDO.methods"
>方法</A
></H3
><P
></P
><UL
><LI
><P
> <A
HREF="function.pdo-begintransaction.html"
>beginTransaction</A
>
- begins a transaction
</P
></LI
><LI
><P
> <A
HREF="function.pdo-commit.html"
>commit</A
>
- commits a transaction
</P
></LI
><LI
><P
> <A
HREF="function.pdo-errorcode.html"
>errorCode</A
>
- retrieves an error code, if any, from the database
</P
></LI
><LI
><P
> <A
HREF="function.pdo-errorinfo.html"
>errorInfo</A
>
- retrieves an array of error information, if any, from the
database
</P
></LI
><LI
><P
> <A
HREF="function.pdo-exec.html"
>exec</A
>
- issues an SQL statement and returns the number of affected rows
</P
></LI
><LI
><P
> <A
HREF="function.pdo-getattribute.html"
>getAttribute</A
>
- retrieves a database connection attribute
</P
></LI
><LI
><P
> <A
HREF="function.pdo-lastinsertid.html"
>lastInsertId</A
>
- retrieves the value of the last row that was inserted into a table
</P
></LI
><LI
><P
> <A
HREF="function.pdo-prepare.html"
>prepare</A
>
- prepares an SQL statement for execution
</P
></LI
><LI
><P
> <A
HREF="function.pdo-query.html"
>query</A
>
- issues an SQL statement and returns a result set
</P
></LI
><LI
><P
> <A
HREF="function.pdo-quote.html"
>quote</A
>
- returns a quoted version of a string for use in SQL statements
</P
></LI
><LI
><P
> <A
HREF="function.pdo-rollback.html"
>rollBack</A
>
- roll back a transaction
</P
></LI
><LI
><P
> <A
HREF="function.pdo-setattribute.html"
>setAttribute</A
>
- sets a database connection attribute
</P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="section"
><H2
CLASS="section"
><A
NAME="pdo.class.PDOStatement"
><B
CLASS="classname"
>PDOStatement</B
></A
></H2
><P
> Represents a prepared statement and, after the statement is executed, an
associated result set.
</P
><DIV
CLASS="section"
><H3
CLASS="section"
><A
NAME="pdo.class.Statement.methods"
>方法</A
></H3
><P
></P
><UL
><LI
><P
> <A
HREF="function.pdostatement-bindcolumn.html"
>bindColumn</A
>
- binds a PHP variable to an output column in a result set
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-bindparam.html"
>bindParam</A
>
- binds a PHP variable to a parameter in the prepared statement
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-bindvalue.html"
>bindValue</A
>
- binds a value to a parameter in the prepared statement
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-closecursor.html"
>closeCursor</A
>
- closes the cursor, allowing the statement to be executed again
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-columncount.html"
>columnCount</A
>
- returns the number of columns in the result set
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-errorcode.html"
>errorCode</A
>
- retrieves an error code, if any, from the statement
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-errorinfo.html"
>errorInfo</A
>
- retrieves an array of error information, if any, from the statement
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-execute.html"
>execute</A
>
- executes a prepared statement
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-fetch.html"
>fetch</A
>
- fetches a row from a result set
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-fetchall.html"
>fetchAll</A
>
- fetches an array containing all of the rows from a result set
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-fetchcolumn.html"
>fetchColumn</A
>
- returns the data from a single column in a result set
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-getattribute.html"
>getAttribute</A
>
- retrieves a PDOStatement attribute
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-getcolumnmeta.html"
>getColumnMeta</A
>
- retrieves metadata for a column in the result set
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-nextrowset.html"
>nextRowset</A
>
- retrieves the next rowset (result set)
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-rowcount.html"
>rowCount</A
>
- returns the number of rows that were affected by the execution of
an SQL statement
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-setattribute.html"
>setAttribute</A
>
- sets a PDOStatement attribute
</P
></LI
><LI
><P
> <A
HREF="function.pdostatement-setfetchmode.html"
>setFetchMode</A
>
- sets the fetch mode for a PDOStatement
</P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="section"
><H2
CLASS="section"
><A
NAME="pdo.class.PDOException"
><B
CLASS="classname"
>PDOException</B
></A
></H2
><P
> Represents an error raised by PDO. You should not throw a
<B
CLASS="classname"
>PDOException</B
> from your own code.
See <A
HREF="language.exceptions.html"
>Exceptions</A
> for more
information about Exceptions in PHP.
</P
><TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN175835"
></A
><P
><B
>例 15. The PDOException class</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br /></font><font color="#007700">class </font><font color="#0000BB">PDOException </font><font color="#007700">extends </font><font color="#0000BB">Exception<br /></font><font color="#007700">{<br /> </font><font color="#0000BB">public $errorInfo </font><font color="#007700">= </font><font color="#0000BB">null</font><font color="#007700">; </font><font color="#FF8000">// corresponds to PDO::errorInfo()<br /> // or PDOStatement::errorInfo()<br /> </font><font color="#0000BB">protected $message</font><font color="#007700">; </font><font color="#FF8000">// textual error message<br /> // use Exception::getMessage() to access it<br /> </font><font color="#0000BB">protected $code</font><font color="#007700">; </font><font color="#FF8000">// SQLSTATE error code<br /> // use Exception::getCode() to access it<br /></font><font color="#007700">}<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
></DIV
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="pdo.constants"
>预定义常量</A
></H1
><P
>以下常量由本扩展模块定义，因此只有在本扩展模块被编译到
PHP 中，或者在运行时被动态加载后才有效。</P
><DIV
CLASS="warning"
><P
></P
><TABLE
CLASS="warning"
BORDER="1"
WIDTH="100%"
><TR
><TD
ALIGN="CENTER"
><B
>警告</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
> PDO uses class constants since PHP 5.1. Prior releases use global constants
in the form <TT
CLASS="constant"
><B
>PDO_PARAM_BOOL</B
></TT
>.
</P
></TD
></TR
></TABLE
></DIV
><P
></P
><DIV
CLASS="variablelist"
><DL
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_BOOL</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Represents a boolean data type.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_NULL</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Represents the SQL NULL data type.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_INT</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Represents the SQL INTEGER data type.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_STR</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Represents the SQL CHAR, VARCHAR, or other string data type.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_LOB</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Represents the SQL large object data type.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_STMT</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Represents a recordset type. Not currently supported by any drivers.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_INPUT_OUTPUT</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the parameter is an INOUT parameter for a stored
procedure. You must bitwise-OR this value with an explicit
PDO::PARAM_* data type.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_LAZY</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return each row as an object with
variable names that correspond to the column names returned in the result
set. PDO::FETCH_LAZY creates the object variable names as they are accessed.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_ASSOC</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return each row as an array indexed
by column name as returned in the corresponding result set. If the result
set contains multiple columns with the same name, PDO::FETCH_ASSOC returns
only a single value per column name.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_NAMED</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return each row as an array indexed
by column name as returned in the corresponding result set. If the result
set contains multiple columns with the same name, PDO::FETCH_NAMED returns
an array of values per column name.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_NUM</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return each row as an array indexed
by column number as returned in the corresponding result set, starting at
column 0.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_BOTH</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return each row as an array indexed
by both column name and number as returned in the corresponding result set,
starting at column 0.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_OBJ</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return each row as an object with
property names that correspond to the column names returned in the result
set.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_BOUND</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return TRUE and assign the values of
the columns in the result set to the PHP variables to which they were
bound with the <B
CLASS="function"
>PDOStatement::bindParam()</B
> or
<B
CLASS="function"
>PDOStatement::bindColumn()</B
> methods.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_COLUMN</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return only a single requested
column from the next row in the result set.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_CLASS</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall return a new instance of the
requested class, mapping the columns to named properties in the class.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_INTO</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Specifies that the fetch method shall update an existing instance of the
requested class, mapping the columns to named properties in the class.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_FUNC</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_GROUP</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_UNIQUE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_CLASSTYPE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_SERIALIZE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Available since PHP 5.1.0.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_PROPS_LATE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Available since PHP 5.2.0
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_AUTOCOMMIT</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> If this value is <TT
CLASS="constant"
><B
>FALSE</B
></TT
>, PDO attempts to disable autocommit so that the
connection begins a transaction.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_PREFETCH</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Setting the prefetch size allows you to balance speed against memory
usage for your application. Not all database/driver combinations support
setting of the prefetch size. A larger prefetch size results in
increased performance at the cost of higher memory usage.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_TIMEOUT</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Sets the timeout value in seconds for communications with the database.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_ERRMODE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> See the <A
HREF="ref.pdo.html#pdo.error-handling"
>Errors and error
handling</A
> section for more information about this attribute.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_SERVER_VERSION</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> This is a read only attribute; it will return information about the
version of the database server to which PDO is connected.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_CLIENT_VERSION</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> This is a read only attribute; it will return information about the
version of the client libraries that the PDO driver is using.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_SERVER_INFO</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> This is a read only attribute; it will return some meta information about the
database server to which PDO is connected.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_CONNECTION_STATUS</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_CASE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Force column names to a specific case specified by the PDO::CASE_*
constants.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_CURSOR_NAME</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Get or set the name to use for a cursor. Most useful when using
scrollable cursors and positioned updates.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_CURSOR</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Selects the cursor type. PDO currently supports either
<TT
CLASS="constant"
><B
>PDO::CURSOR_FWDONLY</B
></TT
> and
<TT
CLASS="constant"
><B
>PDO::CURSOR_SCROLL</B
></TT
>. Stick with
<TT
CLASS="constant"
><B
>PDO::CURSOR_FWDONLY</B
></TT
> unless you know that you need a
scrollable cursor.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_DRIVER_NAME</B
></TT
>
(<A
HREF="language.types.string.html"
><B
CLASS="type"
>string</B
></A
>)</DT
><DD
><P
> Returns the name of the driver.
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN176063"
></A
><P
><B
>例 16. using PDO::ATTR_DRIVER_NAME</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br /></font><font color="#007700">if (</font><font color="#0000BB">$db</font><font color="#007700">-></font><font color="#0000BB">getAttribute</font><font color="#007700">(</font><font color="#0000BB">PDO</font><font color="#007700">::</font><font color="#0000BB">ATTR_DRIVER_NAME</font><font color="#007700">) == </font><font color="#DD0000">'mysql'</font><font color="#007700">) {<br /> echo </font><font color="#DD0000">"Running on mysql; doing something mysql specific here\n"</font><font color="#007700">;<br />}<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_ORACLE_NULLS</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Convert empty strings to SQL NULL values on data fetches.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_PERSISTENT</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
Request a persistent connection, rather than creating a new connection.
See <A
HREF="ref.pdo.html#pdo.connections"
>Connections and Connection
management</A
> for more information on this attribute.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_STATEMENT_CLASS</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_FETCH_CATALOG_NAMES</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
Prepend the containing catalog name to each column name returned in the
result set. The catalog name and column name are separated by a decimal
(.) character. Support of this attribute is at the driver level; it may
not be supported by your driver.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_FETCH_TABLE_NAMES</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
Prepend the containing table name to each column name returned in the
result set. The table name and column name are separated by a decimal (.)
character. Support of this attribute is at the driver level; it may not
be supported by your driver.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_STRINGIFY_FETCHES</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_MAX_COLUMN_LEN</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_DEFAULT_FETCH_MODE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
Available since PHP 5.2.0
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ATTR_EMULATE_PREPARES</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Available since PHP 5.1.3.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ERRMODE_SILENT</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Do not raise an error or exception if an error occurs. The developer is
expected to explicitly check for errors. This is the default mode.
See <A
HREF="ref.pdo.html#pdo.error-handling"
>Errors and error handling</A
>
for more information about this attribute.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ERRMODE_WARNING</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Issue a PHP E_WARNING message if an error occurs.
See <A
HREF="ref.pdo.html#pdo.error-handling"
>Errors and error handling</A
>
for more information about this attribute.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ERRMODE_EXCEPTION</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Throw a <B
CLASS="classname"
>PDOException</B
> if an error occurs.
See <A
HREF="ref.pdo.html#pdo.error-handling"
>Errors and error handling</A
>
for more information about this attribute.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::CASE_NATURAL</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Leave column names as returned by the database driver.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::CASE_LOWER</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
Force column names to lower case.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::CASE_UPPER</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Force column names to upper case.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::NULL_NATURAL</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::NULL_EMPTY_STRING</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::NULL_TO_STRING</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_ORI_NEXT</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Fetch the next row in the result set. Valid only for scrollable cursors.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_ORI_PRIOR</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Fetch the previous row in the result set. Valid only for scrollable
cursors.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_ORI_FIRST</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Fetch the first row in the result set. Valid only for scrollable cursors.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_ORI_LAST</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Fetch the last row in the result set. Valid only for scrollable cursors.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_ORI_ABS</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Fetch the requested row by row number from the result set. Valid only
for scrollable cursors.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::FETCH_ORI_REL</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Fetch the requested row by relative position from the current position
of the cursor in the result set. Valid only for scrollable cursors.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::CURSOR_FWDONLY</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Create a PDOStatement object with a forward-only cursor. This is the
default cursor choice, as it is the fastest and most common data access
pattern in PHP.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::CURSOR_SCROLL</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Create a PDOStatement object with a scrollable cursor. Pass the
PDO::FETCH_ORI_* constants to control the rows fetched from the result set.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::ERR_NONE</B
></TT
>
(<A
HREF="language.types.string.html"
><B
CLASS="type"
>string</B
></A
>)</DT
><DD
><P
>
Corresponds to SQLSTATE '00000', meaning that the SQL statement was
successfully issued with no errors or warnings. This constant is for
your convenience when checking <B
CLASS="function"
>PDO::errorCode()</B
> or
<B
CLASS="function"
>PDOStatement::errorCode()</B
> to determine if an error
occurred. You will usually know if this is the case by examining the
return code from the method that raised the error condition anyway.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_EVT_ALLOC</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Allocation event
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_EVT_FREE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Deallocation event
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_EVT_EXEC_PRE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Event triggered prior to execution of a prepared statement.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_EVT_EXEC_POST</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Event triggered subsequent to execution of a prepared statement.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_EVT_FETCH_PRE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Event triggered prior to fetching a result from a resultset.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_EVT_FETCH_POST</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Event triggered subsequent to fetching a result from a resultset.
</P
></DD
><DT
><TT
CLASS="constant"
><B
>PDO::PARAM_EVT_NORMALIZE</B
></TT
>
(<A
HREF="language.types.integer.html"
><B
CLASS="type"
>integer</B
></A
>)</DT
><DD
><P
> Event triggered during bound parameter registration
allowing the driver to normalize the parameter name.
</P
></DD
></DL
></DIV
></DIV
></DIV
><DIV
CLASS="TOC"
><DL
><DT
><B
>目录</B
></DT
><DT
><A
HREF="function.pdo-begintransaction.html"
>PDO->beginTransaction()</A
> --
Initiates a transaction
</DT
><DT
><A
HREF="function.pdo-commit.html"
>PDO->commit()</A
> --
Commits a transaction
</DT
><DT
><A
HREF="function.pdo-construct.html"
>PDO->__construct()</A
> --
Creates a PDO instance representing a connection to a database
</DT
><DT
><A
HREF="function.pdo-errorcode.html"
>PDO->errorCode()</A
> --
Fetch the SQLSTATE associated with the last operation on the database handle
</DT
><DT
><A
HREF="function.pdo-errorinfo.html"
>PDO->errorInfo()</A
> --
Fetch extended error information associated with the last operation on the database handle
</DT
><DT
><A
HREF="function.pdo-exec.html"
>PDO->exec()</A
> --
Execute an SQL statement and return the number of affected rows
</DT
><DT
><A
HREF="function.pdo-getattribute.html"
>PDO->getAttribute()</A
> --
Retrieve a database connection attribute
</DT
><DT
><A
HREF="function.pdo-getavailabledrivers.html"
>PDO->getAvailableDrivers()</A
> --
Return an array of available PDO drivers
</DT
><DT
><A
HREF="function.pdo-lastinsertid.html"
>PDO->lastInsertId()</A
> --
Returns the ID of the last inserted row or sequence value
</DT
><DT
><A
HREF="function.pdo-prepare.html"
>PDO->prepare()</A
> --
Prepares a statement for execution and returns a statement object
</DT
><DT
><A
HREF="function.pdo-query.html"
>PDO->query()</A
> --
Executes an SQL statement, returning a result set as a PDOStatement object
</DT
><DT
><A
HREF="function.pdo-quote.html"
>PDO->quote()</A
> --
Quotes a string for use in a query.
</DT
><DT
><A
HREF="function.pdo-rollback.html"
>PDO->rollBack()</A
> --
Rolls back a transaction
</DT
><DT
><A
HREF="function.pdo-setattribute.html"
>PDO->setAttribute()</A
> --
Set an attribute
</DT
><DT
><A
HREF="function.pdostatement-bindcolumn.html"
>PDOStatement->bindColumn()</A
> --
Bind a column to a PHP variable
</DT
><DT
><A
HREF="function.pdostatement-bindparam.html"
>PDOStatement->bindParam()</A
> --
Binds a parameter to the specified variable name
</DT
><DT
><A
HREF="function.pdostatement-bindvalue.html"
>PDOStatement->bindValue()</A
> --
Binds a value to a parameter
</DT
><DT
><A
HREF="function.pdostatement-closecursor.html"
>PDOStatement->closeCursor()</A
> --
Closes the cursor, enabling the statement to be executed again.
</DT
><DT
><A
HREF="function.pdostatement-columncount.html"
>PDOStatement->columnCount()</A
> --
Returns the number of columns in the result set
</DT
><DT
><A
HREF="function.pdostatement-errorcode.html"
>PDOStatement->errorCode()</A
> --
Fetch the SQLSTATE associated with the last operation on the statement handle
</DT
><DT
><A
HREF="function.pdostatement-errorinfo.html"
>PDOStatement->errorInfo()</A
> --
Fetch extended error information associated with the last operation on the statement handle
</DT
><DT
><A
HREF="function.pdostatement-execute.html"
>PDOStatement->execute()</A
> --
Executes a prepared statement
</DT
><DT
><A
HREF="function.pdostatement-fetch.html"
>PDOStatement->fetch()</A
> --
Fetches the next row from a result set
</DT
><DT
><A
HREF="function.pdostatement-fetchall.html"
>PDOStatement->fetchAll()</A
> --
Returns an array containing all of the result set rows
</DT
><DT
><A
HREF="function.pdostatement-fetchcolumn.html"
>PDOStatement->fetchColumn()</A
> --
Returns a single column from the next row of a result set
</DT
><DT
><A
HREF="function.pdostatement-fetchobject.html"
>PDOStatement->fetchObject()</A
> -- Fetches the next row and returns it as an object.</DT
><DT
><A
HREF="function.pdostatement-getattribute.html"
>PDOStatement->getAttribute()</A
> --
Retrieve a statement attribute
</DT
><DT
><A
HREF="function.pdostatement-getcolumnmeta.html"
>PDOStatement->getColumnMeta()</A
> --
Returns metadata for a column in a result set
</DT
><DT
><A
HREF="function.pdostatement-nextrowset.html"
>PDOStatement->nextRowset()</A
> --
Advances to the next rowset in a multi-rowset statement handle
</DT
><DT
><A
HREF="function.pdostatement-rowcount.html"
>PDOStatement->rowCount()</A
> --
Returns the number of rows affected by the last SQL statement
</DT
><DT
><A
HREF="function.pdostatement-setattribute.html"
>PDOStatement->setAttribute()</A
> --
Set a statement attribute
</DT
><DT
><A
HREF="function.pdostatement-setfetchmode.html"
>PDOStatement->setFetchMode()</A
> --
Set the default fetch mode for this statement
</DT
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