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110 lines
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HTML
110 lines
8.8 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>Rolls back a transaction</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.db2-rollback" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">db2_rollback</h1>
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<p class="verinfo">(PECL ibm_db2 >= 1.0.0)</p><p class="refpurpose"><span class="refname">db2_rollback</span> — <span class="dc-title">
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Rolls back a transaction
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</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.db2-rollback-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>db2_rollback</strong></span>
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( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$connection</code></span>
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) : <span class="type">bool</span></div>
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<p class="para rdfs-comment">
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Rolls back an in-progress transaction on the specified connection resource and
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begins a new transaction. PHP applications normally default to AUTOCOMMIT
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mode, so <span class="function"><strong>db2_rollback()</strong></span> normally has no effect unless
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AUTOCOMMIT has been turned off for the connection resource.
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.db2-rollback-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">connection</code></dt>
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<dd>
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<p class="para">
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A valid database connection resource variable as returned from
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<span class="function"><a href="db2_connect.html" class="function">db2_connect()</a></span> or <span class="function"><a href="db2_pconnect.html" class="function">db2_pconnect()</a></span>.
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</p>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.db2-rollback-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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成功时返回 <strong><code>TRUE</code></strong>， 或者在失败时返回 <strong><code>FALSE</code></strong>。
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.db2-rollback-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-1272">
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<p><strong>Example #1 Rolling back a DELETE statement</strong></p>
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<div class="example-contents"><p>
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In the following example, we count the number of rows in a table, turn
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off AUTOCOMMIT mode on a database connection, delete all of the rows in
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the table and return the count of <em>0</em> to prove that the
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rows have been removed. We then issue <span class="function"><strong>db2_rollback()</strong></span>
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and return the updated count of rows in the table to show that the number
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is the same as before we issued the DELETE statement. The return to the
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original state of the table demonstrates that the roll back of the
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transaction succeeded.
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</p></div>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<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>
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</span>
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</pre></div>
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</div>
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<div class="example-contents"><p>以上例程会输出：</p></div>
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<div class="example-contents screen">
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<div class="cdata"><pre>
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7
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0
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7
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</pre></div>
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</div>
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</div>
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</p>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.db2-rollback-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="db2_autocommit.html" class="function" rel="rdfs-seeAlso">db2_autocommit()</a> - Returns or sets the AUTOCOMMIT state for a database connection</span></li>
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<li class="member"><span class="function"><a href="db2_commit.html" class="function" rel="rdfs-seeAlso">db2_commit()</a> - Commits a transaction</span></li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |