php-doc-en/reference/pdo/functions/PDO-rollBack.xml

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  <refentry id="function.PDO-rollBack">
   <refnamediv>
    <refname>PDO::rollBack</refname>
    <refpurpose>
     Rolls back a transaction
    </refpurpose>
   </refnamediv>

   <refsect1 role="description">
    &reftitle.description;
    <methodsynopsis>
     <type>bool</type><methodname>PDO::rollBack</methodname>
     <void/>
    </methodsynopsis>

    <para>
     Rolls back the current transaction, as initiated by
     <function>PDO::beginTransaction</function>.  It is an error to call this
     method if no transaction is active.
    </para>
    <para>
     If the database was set to autocommit mode, this function will restore
     autocommit mode after it has rolled back the transaction.
    </para>
    <para>
     Some databases, including MySQL, automatically issue an implicit
     COMMIT when a database definition language (DDL) statement such as
     DROP TABLE or CREATE TABLE is issued within a transaction. The implicit
     COMMIT will prevent you from rolling back any other changes within the
     transaction boundary.
    </para>
   </refsect1>

   <refsect1 role="examples">
    &reftitle.examples;
    <para>
     <example><title>Roll back a transaction</title>
      <para>
       The following example begins a transaction and issues two statements
       that modify the database before rolling back the changes. On MySQL,
       however, the DROP TABLE statement automatically commits the
       transaction so that none of the changes in the transaction are rolled
       back.
      </para>
      <programlisting role='php'>
<![CDATA[
<?php
/* Begin a transaction, turning off autocommit */
$dbh->beginTransaction();

/* Change the database schema and data */
$sth = $dbh->exec("DROP TABLE fruit");
$sth = $dbh->exec("UPDATE dessert
    SET name = 'hamburger'");

/* Recognize mistake and roll back changes */
$dbh->rollBack();

/* Database connection is now back in autocommit mode */
?>
]]>
      </programlisting>
     </example>
    </para>
   </refsect1>

   <refsect1 role="seealso">
    &reftitle.seealso;
    <para>
     <simplelist>
      <member><function>PDO::beginTransaction</function></member>
      <member><function>PDO::commit</function></member>
     </simplelist>
    </para>
   </refsect1>


  </refentry>

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