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79 lines
3.8 KiB
HTML
79 lines
3.8 KiB
HTML
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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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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>Logically renumbering records</title>
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<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB Upgrade Guide" />
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<link rel="up" href="upgrade_3_2_toc.html" title="Chapter 12. Upgrading Berkeley DB 3.1 applications to Berkeley DB 3.2" />
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<link rel="prev" href="upgrade_3_2_callback.html" title="DB callback functions, app_private field" />
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<link rel="next" href="upgrade_3_2_incomplete.html" title="DB_INCOMPLETE" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 11.2.5.2</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">Logically renumbering records</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="upgrade_3_2_callback.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 12. Upgrading Berkeley DB 3.1 applications to Berkeley DB 3.2</th>
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<td width="20%" align="right"> <a accesskey="n" href="upgrade_3_2_incomplete.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="upgrade_3_2_renumber"></a>Logically renumbering records</h2>
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</div>
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</div>
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</div>
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<p>In the Berkeley DB 3.2 release, cursor adjustment semantics changed for Recno
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databases with mutable record numbers. Before the 3.2 release, cursors
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were adjusted to point to the previous or next record at the time the
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record to which the cursor referred was deleted. This could lead to
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unexpected behaviors. For example, two cursors referring to sequential
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records that were both deleted would lose their relationship to each
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other and would refer to the same position in the database instead of
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their original sequential relationship. There were also command
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sequences that would have unexpected results. For example, DB_AFTER
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and DB_BEFORE cursor put operations, using a cursor previously used to
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delete an item, would perform the put relative to the cursor's adjusted
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position and not its original position.</p>
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<p>In the Berkeley DB 3.2 release, cursors maintain their position in the tree
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regardless of deletion operations using the cursor. Applications that
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perform database operations, using cursors previously used to delete
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entries in Recno databases with mutable record numbers, should be
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evaluated to ensure that the new semantics do not cause application
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failure.</p>
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</div>
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<div class="navfooter">
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<hr />
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<table width="100%" summary="Navigation footer">
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<tr>
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<td width="40%" align="left"><a accesskey="p" href="upgrade_3_2_callback.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="upgrade_3_2_toc.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="upgrade_3_2_incomplete.html">Next</a></td>
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</tr>
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<tr>
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<td width="40%" align="left" valign="top">DB callback functions, app_private field </td>
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<td width="20%" align="center">
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<a accesskey="h" href="index.html">Home</a>
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</td>
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<td width="40%" align="right" valign="top"> DB_INCOMPLETE</td>
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</tr>
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</table>
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</div>
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</body>
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</html>
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