function.db2-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="function.db2-result.html">db2_result</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.db2-server-info.html">db2_server_info</a></div> <div class="up"><a href="ref.ibm-db2.html">IBM DB2 Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.db2-rollback" class="refentry"> <div class="refnamediv"> <h1 class="refname">db2_rollback</h1> <p class="verinfo">(PECL ibm_db2:1.0-1.6.2)</p><p class="refpurpose"><span class="refname">db2_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>db2_rollback</b></b></span> ( <span class="methodparam"><span class="type">resource</span> <tt class="parameter">$connection</tt></span> )</div> <p class="para rdfs-comment"> Rolls back an in-progress transaction on the specified connection resource and begins a new transaction. PHP applications normally default to AUTOCOMMIT mode, so <b>db2_rollback()</b> normally has no effect unless AUTOCOMMIT has been turned off for the connection resource. </p> <blockquote><p><b class="note">Note</b>: If the specified connection resource is a persistent connection, all transactions in progress for all applications using that persistent connection will be rolled back. For this reason, persistent connections are not recommended for use in applications that require transactions. <br /> </p></blockquote> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">connection</tt></i></span> <dd> <p class="para"> A valid database connection resource variable as returned from <a href="function.db2-connect.html" class="function">db2_connect()</a> or <a href="function.db2-pconnect.html" class="function">db2_pconnect()</a>. </p> </dd> </dt> </dl> </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 Rolling back a DELETE statement</b></p> <div class="example-contents"><p> In the following example, we count the number of rows in a table, turn off AUTOCOMMIT mode on a database connection, delete all of the rows in the table and return the count of <i>0</i> to prove that the rows have been removed. We then issue <b>db2_rollback()</b> and return the updated count of rows in the table to show that the number is the same as before we issued the DELETE statement. The return to the original state of the table demonstrates that the roll back of the transaction succeeded. </p></div> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$conn </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_connect</span><span style="color: #007700">(</span><span style="color: #0000BB">$database</span><span style="color: #007700">, </span><span style="color: #0000BB">$user</span><span style="color: #007700">, </span><span style="color: #0000BB">$password</span><span style="color: #007700">);<br /><br />if (</span><span style="color: #0000BB">$conn</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$stmt </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_exec</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #DD0000">"SELECT count(*) FROM animals"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_fetch_array</span><span style="color: #007700">( </span><span style="color: #0000BB">$stmt </span><span style="color: #007700">);<br /> echo </span><span style="color: #0000BB">$res</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">] . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /> <br /> </span><span style="color: #FF8000">// Turn AUTOCOMMIT off<br /> </span><span style="color: #0000BB">db2_autocommit</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #0000BB">DB2_AUTOCOMMIT_OFF</span><span style="color: #007700">);<br /> <br /> </span><span style="color: #FF8000">// Delete all rows from ANIMALS<br /> </span><span style="color: #0000BB">db2_exec</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #DD0000">"DELETE FROM animals"</span><span style="color: #007700">);<br /> <br /> </span><span style="color: #0000BB">$stmt </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_exec</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #DD0000">"SELECT count(*) FROM animals"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_fetch_array</span><span style="color: #007700">( </span><span style="color: #0000BB">$stmt </span><span style="color: #007700">);<br /> echo </span><span style="color: #0000BB">$res</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">] . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /> <br /> </span><span style="color: #FF8000">// Roll back the DELETE statement<br /> </span><span style="color: #0000BB">db2_rollback</span><span style="color: #007700">( </span><span style="color: #0000BB">$conn </span><span style="color: #007700">);<br /> <br /> </span><span style="color: #0000BB">$stmt </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_exec</span><span style="color: #007700">( </span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #DD0000">"SELECT count(*) FROM animals" </span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_fetch_array</span><span style="color: #007700">( </span><span style="color: #0000BB">$stmt </span><span style="color: #007700">);<br /> echo </span><span style="color: #0000BB">$res</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">] . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">db2_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">);<br />}<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> <div class="example-contents"><p>The above example will output:</p></div> <div class="example-contents"><pre><div class="cdata"><pre>707</pre></div> </pre></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="function.db2-autocommit.html" class="function" rel="rdfs-seeAlso">db2_autocommit()</a></li> <li class="member"><a href="function.db2-commit.html" class="function" rel="rdfs-seeAlso">db2_commit()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.db2-result.html">db2_result</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.db2-server-info.html">db2_server_info</a></div> <div class="up"><a href="ref.ibm-db2.html">IBM DB2 Functions</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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