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239 lines
10 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::upgrade()</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="dbtruncate.html" title="Db::truncate()" />
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<link rel="next" href="dbverify.html" title="Db::verify()" />
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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">Db::upgrade()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="dbtruncate.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="dbverify.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="dbupgrade"></a>Db::upgrade()</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_cxx.h>
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int
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Db::upgrade(const char *file, u_int32_t flags);</pre>
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<p>
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The <code class="methodname">Db::upgrade()</code> method upgrades all of the databases included in
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the file <span class="bold"><strong>file</strong></span>, if necessary. If no
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upgrade is necessary, <code class="methodname">Db::upgrade()</code> always returns success.
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</p>
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<p>
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<span class="bold"><strong>Database upgrades 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 upgraded. See <a href="../../programmer_reference/am_upgrade.html" class="olink">Upgrading databases</a> for more
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information.</strong></span>
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</p>
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<p>
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Unlike all other database operations, <code class="methodname">Db::upgrade()</code> may only be done
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on a system with the same byte-order as the database.
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</p>
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<p>
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The <code class="methodname">Db::upgrade()</code> <span>
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<span>
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method either returns a non-zero error value or throws an
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exception that encapsulates a non-zero error value on
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failure, and returns 0 on success.
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</span>
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</span>
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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="id3602363"></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="id3602374"></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 upgraded.
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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="id3602508"></a>flags</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>flags</strong></span> parameter must be set to 0
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or the following value:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p><a id="upgrade_DB_DUPSORT"></a>
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<code class="literal">DB_DUPSORT</code>
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</p>
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<p>
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<span class="bold"><strong>This flag is only meaningful when upgrading
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databases from releases before the Berkeley DB 3.1 release.</strong></span>
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</p>
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<p>
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As part of the upgrade from the Berkeley DB 3.0 release to the 3.1
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release, the on-disk format of duplicate data items changed. To
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correctly upgrade the format requires applications to specify whether
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duplicate data items in the database are sorted or not. Specifying
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the DB_DUPSORT flag informs <code class="methodname">Db::upgrade()</code> that the duplicates are
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sorted; otherwise they are assumed to be unsorted. Incorrectly
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specifying the value of this flag may lead to database corruption.
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</p>
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<p>
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Further, because the <code class="methodname">Db::upgrade()</code> method upgrades a physical file
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(including all the databases it contains), it is not possible to use
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<code class="methodname">Db::upgrade()</code> to upgrade files in which some of the databases it
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includes have sorted duplicate data items, and some of the databases
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it includes have unsorted duplicate data items. If the file does not
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have more than a single database, if the databases do not support
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duplicate data items, or if all of the databases that support
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duplicate data items support the same style of duplicates (either
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sorted or unsorted), <code class="methodname">Db::upgrade()</code> will work correctly as long as the
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DB_DUPSORT flag is correctly specified. Otherwise, the file cannot be
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upgraded using <code class="methodname">Db::upgrade;()</code> it must be upgraded manually by dumping
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and reloading the databases.
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</p>
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</li>
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</ul>
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</div>
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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="id3602686"></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::upgrade()</code> is affected by any database directory specified using the
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<a class="xref" href="envset_data_dir.html" title="DbEnv::set_data_dir()">DbEnv::set_data_dir()</a>
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method, or by setting the "set_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="id3602159"></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::upgrade()</code> <span>
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<span>
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method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
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exception, encapsulating one of the following non-zero errors, or return one
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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="id3602836"></a>DB_OLD_VERSION</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 cannot be upgraded by this version of the Berkeley DB
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software.
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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="id3602818"></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="id3602763"></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="dbtruncate.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="dbverify.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::truncate() </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::verify()</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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