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diff --git a/doc/src/sgml/html/sql-savepoint.html b/doc/src/sgml/html/sql-savepoint.html new file mode 100644 index 0000000..8c32dcd --- /dev/null +++ b/doc/src/sgml/html/sql-savepoint.html @@ -0,0 +1,79 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>SAVEPOINT</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="sql-rollback-to.html" title="ROLLBACK TO SAVEPOINT" /><link rel="next" href="sql-security-label.html" title="SECURITY LABEL" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">SAVEPOINT</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-rollback-to.html" title="ROLLBACK TO SAVEPOINT">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-security-label.html" title="SECURITY LABEL">Next</a></td></tr></table><hr /></div><div class="refentry" id="SQL-SAVEPOINT"><div class="titlepage"></div><a id="id-1.9.3.170.1" class="indexterm"></a><a id="id-1.9.3.170.2" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">SAVEPOINT</span></h2><p>SAVEPOINT — define a new savepoint within the current transaction</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis"> +SAVEPOINT <em class="replaceable"><code>savepoint_name</code></em> +</pre></div><div class="refsect1" id="id-1.9.3.170.6"><h2>Description</h2><p> + <code class="command">SAVEPOINT</code> establishes a new savepoint within + the current transaction. + </p><p> + A savepoint is a special mark inside a transaction that allows all commands + that are executed after it was established to be rolled back, restoring + the transaction state to what it was at the time of the savepoint. + </p></div><div class="refsect1" id="id-1.9.3.170.7"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>savepoint_name</code></em></span></dt><dd><p> + The name to give to the new savepoint. If savepoints with the + same name already exist, they will be inaccessible until newer + identically-named savepoints are released. + </p></dd></dl></div></div><div class="refsect1" id="id-1.9.3.170.8"><h2>Notes</h2><p> + Use <a class="link" href="sql-rollback-to.html" title="ROLLBACK TO SAVEPOINT"><code class="command">ROLLBACK TO</code></a> to + rollback to a savepoint. Use <a class="link" href="sql-release-savepoint.html" title="RELEASE SAVEPOINT"><code class="command">RELEASE SAVEPOINT</code></a> + to destroy a savepoint, keeping + the effects of commands executed after it was established. + </p><p> + Savepoints can only be established when inside a transaction block. + There can be multiple savepoints defined within a transaction. + </p></div><div class="refsect1" id="id-1.9.3.170.9"><h2>Examples</h2><p> + To establish a savepoint and later undo the effects of all commands executed + after it was established: +</p><pre class="programlisting"> +BEGIN; + INSERT INTO table1 VALUES (1); + SAVEPOINT my_savepoint; + INSERT INTO table1 VALUES (2); + ROLLBACK TO SAVEPOINT my_savepoint; + INSERT INTO table1 VALUES (3); +COMMIT; +</pre><p> + The above transaction will insert the values 1 and 3, but not 2. + </p><p> + To establish and later destroy a savepoint: +</p><pre class="programlisting"> +BEGIN; + INSERT INTO table1 VALUES (3); + SAVEPOINT my_savepoint; + INSERT INTO table1 VALUES (4); + RELEASE SAVEPOINT my_savepoint; +COMMIT; +</pre><p> + The above transaction will insert both 3 and 4. + </p><p> + To use a single savepoint name: +</p><pre class="programlisting"> +BEGIN; + INSERT INTO table1 VALUES (1); + SAVEPOINT my_savepoint; + INSERT INTO table1 VALUES (2); + SAVEPOINT my_savepoint; + INSERT INTO table1 VALUES (3); + + -- rollback to the second savepoint + ROLLBACK TO SAVEPOINT my_savepoint; + SELECT * FROM table1; -- shows rows 1 and 2 + + -- release the second savepoint + RELEASE SAVEPOINT my_savepoint; + + -- rollback to the first savepoint + ROLLBACK TO SAVEPOINT my_savepoint; + SELECT * FROM table1; -- shows only row 1 +COMMIT; +</pre><p> + The above transaction shows row 3 being rolled back first, then row 2. + </p></div><div class="refsect1" id="id-1.9.3.170.10"><h2>Compatibility</h2><p> + SQL requires a savepoint to be destroyed automatically when another + savepoint with the same name is established. In + <span class="productname">PostgreSQL</span>, the old savepoint is kept, though only the more + recent one will be used when rolling back or releasing. (Releasing the + newer savepoint with <code class="command">RELEASE SAVEPOINT</code> will cause the older one + to again become accessible to <code class="command">ROLLBACK TO SAVEPOINT</code> and + <code class="command">RELEASE SAVEPOINT</code>.) Otherwise, <code class="command">SAVEPOINT</code> is + fully SQL conforming. + </p></div><div class="refsect1" id="id-1.9.3.170.11"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-begin.html" title="BEGIN"><span class="refentrytitle">BEGIN</span></a>, <a class="xref" href="sql-commit.html" title="COMMIT"><span class="refentrytitle">COMMIT</span></a>, <a class="xref" href="sql-release-savepoint.html" title="RELEASE SAVEPOINT"><span class="refentrytitle">RELEASE SAVEPOINT</span></a>, <a class="xref" href="sql-rollback.html" title="ROLLBACK"><span class="refentrytitle">ROLLBACK</span></a>, <a class="xref" href="sql-rollback-to.html" title="ROLLBACK TO SAVEPOINT"><span class="refentrytitle">ROLLBACK TO SAVEPOINT</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-rollback-to.html" title="ROLLBACK TO SAVEPOINT">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-security-label.html" title="SECURITY LABEL">Next</a></td></tr><tr><td width="40%" align="left" valign="top">ROLLBACK TO SAVEPOINT </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> SECURITY LABEL</td></tr></table></div></body></html>
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