📄 pdo.rollback.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Rolls back a transaction</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="pdo.quote.html">PDO::quote</a></div> <div class="next" style="text-align: right; float: right;"><a href="pdo.setattribute.html">PDO::setAttribute</a></div> <div class="up"><a href="class.pdo.html">PDO</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="pdo.rollback" class="refentry"> <div class="refnamediv"> <h1 class="refname">PDO::rollBack</h1> <p class="verinfo">(PHP 5 >= 5.1.0, PECL pdo:0.1-1.0.3)</p><p class="refpurpose"><span class="refname">PDO::rollBack</span> — <span class="dc-title"> Rolls back a transaction </span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><b><b>PDO::rollBack</b></b></span> ( <span class="methodparam">void</span> )</div> <p class="para rdfs-comment"> Rolls back the current transaction, as initiated by <a href="pdo.begintransaction.html" class="function">PDO::beginTransaction()</a>. It is an error to call this method if no transaction is active. </p> <p class="para"> If the database was set to autocommit mode, this function will restore autocommit mode after it has rolled back the transaction. </p> <p class="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. </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns <b><tt>TRUE</tt></b> on success or <b><tt>FALSE</tt></b> on failure. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"><p><b>Example #1 Roll back a transaction</b></p> <div class="example-contents"><p> 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. </p></div> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">/* Begin a transaction, turning off autocommit */<br /></span><span style="color: #0000BB">$dbh</span><span style="color: #007700">-></span><span style="color: #0000BB">beginTransaction</span><span style="color: #007700">();<br /><br /></span><span style="color: #FF8000">/* Change the database schema and data */<br /></span><span style="color: #0000BB">$sth </span><span style="color: #007700">= </span><span style="color: #0000BB">$dbh</span><span style="color: #007700">-></span><span style="color: #0000BB">exec</span><span style="color: #007700">(</span><span style="color: #DD0000">"DROP TABLE fruit"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$sth </span><span style="color: #007700">= </span><span style="color: #0000BB">$dbh</span><span style="color: #007700">-></span><span style="color: #0000BB">exec</span><span style="color: #007700">(</span><span style="color: #DD0000">"UPDATE dessert<br /> SET name = 'hamburger'"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* Recognize mistake and roll back changes */<br /></span><span style="color: #0000BB">$dbh</span><span style="color: #007700">-></span><span style="color: #0000BB">rollBack</span><span style="color: #007700">();<br /><br /></span><span style="color: #FF8000">/* Database connection is now back in autocommit mode */<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="pdo.begintransaction.html" class="function" rel="rdfs-seeAlso">PDO::beginTransaction()</a></li> <li class="member"><a href="pdo.commit.html" class="function" rel="rdfs-seeAlso">PDO::commit()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="pdo.quote.html">PDO::quote</a></div> <div class="next" style="text-align: right; float: right;"><a href="pdo.setattribute.html">PDO::setAttribute</a></div> <div class="up"><a href="class.pdo.html">PDO</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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