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1257278519
git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@197576 c90b9560-bf6c-de11-be94-00142212c4b1
74 lines
2.7 KiB
XML
74 lines
2.7 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!-- $Revision: 1.2 $ -->
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<sect1 id="internals.pdo.error-handling">
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<title>Error handling</title>
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<para>
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Error handling is implemented using a hand-shaking protocol between
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PDO and the database driver code. The database driver code
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signals PDO than an error has occurred via a failure
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(<literal>0</literal>) return from any of the interface functions. If a zero
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is returned, the field <parameter>error_code</parameter> in the control block appropriate to the
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context (either the pdo_dbh_t or pdo_stmt_t block). In practice, it is
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probably a good idea to set the field in both blocks to the same value to
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ensure the correct one is getting used.
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</para>
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<para>
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The error_mode field is a six-byte field containing a 5 character ASCIIZ
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SQLSTATE identifier code. This code drives the error message process. The
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SQLSTATE code is used to look up an error message in the internal PDO error
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message table (see pdo_sqlstate.c for a list of error codes and their
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messages). If the code is not known to PDO, a default
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<quote>Unknown Message</quote> value will be used.
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</para>
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<para>
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In addition to the SQLSTATE code and error message, PDO will
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call the driver-specific fetch_err() routine to obtain supplemental data
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for the particular error condition. This routine is passed an array into
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which the driver may place additional information. This array has slot
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positions assigned to particular types of supplemental info:
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</para>
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<orderedlist>
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<listitem>
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<para>
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A native error code. This will frequently be an error code obtained
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from the database API.
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</para>
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</listitem>
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<listitem>
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<para>
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A descriptive string. This string can contain anything additional
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information related to the failure. Database drivers typically include
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information such as an error message, code location of the failure, and
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any additional descriptive information the driver developer feels
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worthy of inclusion. It is generally a good idea to include all
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diagnostic information obtainable
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from the database interface at the time of the failure. For
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driver-detected errors (such as memory allocation problems), the driver
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developer can define whatever error information that seems appropriate.
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</para>
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</listitem>
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</orderedlist>
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</sect1>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"../../manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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