mirror of
https://github.com/yasuhirokimura/db18
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Yasuhiro KIMURA
228 lines
8.7 KiB
HTML
228 lines
8.7 KiB
HTML
<?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>DB->convert()</title>
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<link rel="stylesheet" href="apiReference.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 C API Reference" />
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<link rel="up" href="db.html" title="Chapter 2. The DB Handle" />
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<link rel="prev" href="dbcompact.html" title="DB->compact()" />
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<link rel="next" href="db_copy.html" title="db_copy" />
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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 18.1.40</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">
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<span xmlns="http://www.w3.org/1999/xhtml">DB->convert()</span>
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</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="dbcompact.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 2.
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The DB Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="db_copy.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="dbconvert"></a>
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<span>DB->convert()</span>
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</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">#include <db.h>
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int
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DB->convert(DB *db, const char *file, u_int32_t lorder); </pre>
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<p>
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The <code class="methodname">DB->convert()</code> method converts all of the databases included in
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the file <span class="bold"><strong>file</strong></span> to a specified byte order, if necessary.
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If no conversion is necessary, <code class="methodname">DB->convert()</code> always returns success.
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</p>
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<p>
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If the database is partitioned, <a class="xref" href="dbset_partition.html" title="DB->set_partition()">
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<span>DB->set_partition()</span>
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</a>
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must be called before this method in order to convert all database partitions.
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</p>
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<p>
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<span class="bold"><strong>Database conversions are done in place and are
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destructive. For example, if pages need to be allocated and no disk
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space is available, the database may be left corrupted. Backups
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should be made before databases are converted.</strong></span>
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</p>
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<p>
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The <code class="methodname">DB->convert()</code> method is non-atomic
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when used on a partitioned or sliced database, or a database with
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multiple queue extent files. If the operation fails, it is
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possible for the underlying database files to be in an
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inconsistent state.
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</p>
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<p>
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The <code class="methodname">DB->convert()</code> <span>
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<span>
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method returns a non-zero error value on failure and 0 on success.
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</span>
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</span>
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</p>
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<p>
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The <code class="methodname">DB->convert()</code> method is the underlying method used by the <a class="link" href="db_convert.html" title="db_convert">db_convert</a> utility. See the
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<a class="link" href="db_convert.html" title="db_convert">db_convert</a> utility
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source code for an example of using <code class="methodname">DB->convert()</code> in a IEEE/ANSI Std
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1003.1 (POSIX) environment.
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</p>
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<div class="sect2" 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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<h3 class="title"><a id="idm139753806445360"></a>Parameters</h3>
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</div>
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</div>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="idm139753806444976"></a>file</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>file</strong></span> parameter is the physical
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file containing the databases to be converted.
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</p>
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</div>
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<div class="sect3" 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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<h4 class="title"><a id="idm139753806508432"></a>lorder</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>lorder</strong></span> parameter should represent
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the byte order as an integer; for example, big endian order is the number
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4,321, and little endian order is the number 1,234.
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</p>
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</div>
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</div>
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<div class="sect2" 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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<h3 class="title"><a id="idm139753806511488"></a>Environment Variables</h3>
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</div>
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</div>
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</div>
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<p>
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If the database was opened within a database environment, the
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environment variable <code class="literal">DB_HOME</code> may be used as the path of the
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database environment home.
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</p>
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<p>
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<code class="methodname">DB->convert()</code> is affected by any database directory specified using the
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<a class="xref" href="envadd_data_dir.html" title="DB_ENV->add_data_dir()">
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<span>DB_ENV->add_data_dir()</span>
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</a>
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method, or by setting the "add_data_dir" string
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in the environment's <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file.
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</p>
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</div>
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<div class="sect2" 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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<h3 class="title"><a id="idm139753806482144"></a>Errors</h3>
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</div>
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</div>
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</div>
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<p>
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The <code class="methodname">DB->convert()</code> <span>
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<span>
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method may fail and return one of the following non-zero errors:
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</span>
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</span>
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</p>
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<div class="sect3" 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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<h4 class="title"><a id="idm139753806441376"></a>EINVAL</h4>
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</div>
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</div>
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</div>
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<p>
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The database is corrupted or the the database is encrypted but
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the password is not provided.
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</p>
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</div>
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</div>
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<div class="sect2" 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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<h3 class="title"><a id="idm139753806443968"></a>Class</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="link" href="db.html" title="Chapter 2. The DB Handle">DB</a>
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</p>
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</div>
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<div class="sect2" 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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<h3 class="title"><a id="idm139753806438896"></a>See Also</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a>
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</p>
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</div>
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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="dbcompact.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="db.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="db_copy.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">
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<span>DB->compact()</span>
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</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_copy</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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