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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 13:44:03 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 13:44:03 +0000
commit293913568e6a7a86fd1479e1cff8e2ecb58d6568 (patch)
treefc3b469a3ec5ab71b36ea97cc7aaddb838423a0c /doc/src/sgml/html/sql-savepoint.html
parentInitial commit. (diff)
downloadpostgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.tar.xz
postgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.zip
Adding upstream version 16.2.upstream/16.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+<!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 16.2 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 16.2 Documentation">Home</a></td><td width="40%" align="right" valign="top"> SECURITY LABEL</td></tr></table></div></body></html> \ No newline at end of file
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