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03cc650911
The example given was confusing and misleading. If the purpose of it is to show how to get the count of matching records from the database then the example can be much shorter. `query()` should not be checked with `if` statement and there should not be 2 separate queries to the database if the actual count is not needed. If the number of fetched records is needed then you can simply use PHP's `count()` function. git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@351083 c90b9560-bf6c-de11-be94-00142212c4b1
139 lines
3.8 KiB
XML
139 lines
3.8 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<refentry xml:id="pdostatement.rowcount" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>PDOStatement::rowCount</refname>
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<refpurpose>
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Returns the number of rows affected by the last SQL statement
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</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<modifier>public</modifier> <type>int</type><methodname>PDOStatement::rowCount</methodname>
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<void/>
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</methodsynopsis>
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<para>
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<function>PDOStatement::rowCount</function> returns the number of
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rows affected by the last DELETE, INSERT, or UPDATE statement
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executed by the corresponding <literal>PDOStatement</literal> object.
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</para>
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<para>
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If the last SQL statement executed by the associated
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<literal>PDOStatement</literal> was a SELECT statement, some databases
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may return the number of rows returned by that statement. However, this
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behaviour is not guaranteed for all databases and should not be relied
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on for portable applications.
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</para>
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<note>
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<para>
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This method returns "0" (zero) with the SQLite driver at all times,
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and with the PostgreSQL driver only when setting the
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<constant>PDO::ATTR_CURSOR</constant> statement attribute to
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<constant>PDO::CURSOR_SCROLL</constant>.
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</para>
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</note>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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Returns the number of rows.
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</para>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<example>
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<title>Return the number of deleted rows</title>
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<para>
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<function>PDOStatement::rowCount</function> returns the number of
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rows affected by a DELETE, INSERT, or UPDATE statement.
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</para>
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<programlisting role="php">
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<![CDATA[
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<?php
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/* Delete all rows from the FRUIT table */
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$del = $dbh->prepare('DELETE FROM fruit');
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$del->execute();
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/* Return number of rows that were deleted */
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print("Return number of rows that were deleted:\n");
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$count = $del->rowCount();
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print("Deleted $count rows.\n");
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?>
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]]>
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</programlisting>
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&example.outputs.similar;
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<screen>
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<![CDATA[
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Return number of rows that were deleted:
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Deleted 9 rows.
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]]>
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</screen>
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</example>
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<example>
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<title>Counting rows returned by a SELECT statement</title>
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<para>
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For most databases, <function>PDOStatement::rowCount</function> does not
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return the number of rows affected by a SELECT statement. Instead, use
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<function>PDO::query</function> to issue a SELECT COUNT(*) statement
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with the same predicates as your intended SELECT statement, then use
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<function>PDOStatement::fetchColumn</function> to retrieve the number
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of matching rows.
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</para>
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<programlisting role="php">
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<![CDATA[
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<?php
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$sql = "SELECT COUNT(*) FROM fruit WHERE calories > 100";
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$res = $conn->query($sql);
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$count = $res->fetchColumn();
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print "There are " . $count . " matching records.";
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]]>
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</programlisting>
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&example.outputs.similar;
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<screen>
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<![CDATA[
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There are 2 matching records.
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]]>
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</screen>
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</example>
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</para>
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</refsect1>
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<refsect1 role="seealso">
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&reftitle.seealso;
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<para>
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<simplelist>
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<member><function>PDOStatement::columnCount</function></member>
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<member><function>PDOStatement::fetchColumn</function></member>
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<member><function>PDO::query</function></member>
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</simplelist>
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</para>
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</refsect1>
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</refentry>
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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:"~/.phpdoc/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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