mirror of
https://github.com/yasuhirokimura/db18
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Yasuhiro KIMURA
206 lines
7.8 KiB
HTML
206 lines
7.8 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>Chapter 9. The Berkeley DB Environment</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 Programmer's Reference Guide" />
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<link rel="up" href="index.html" title="Berkeley DB Programmer's Reference Guide" />
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<link rel="prev" href="arch_utilities.html" title="Supporting utilities" />
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<link rel="next" href="env_create.html" title="Creating a database environment" />
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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">Chapter 9. The Berkeley DB Environment </th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="arch_utilities.html">Prev</a> </td>
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<th width="60%" align="center"> </th>
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<td width="20%" align="right"> <a accesskey="n" href="env_create.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="chapter" 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"><a id="env"></a>Chapter 9. The Berkeley DB Environment </h2>
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</div>
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</div>
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</div>
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<div class="toc">
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<p>
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<b>Table of Contents</b>
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</p>
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<dl>
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<dt>
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<span class="sect1">
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<a href="env.html#env_intro">Database environment introduction</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_create.html">Creating a database
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environment</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_size.html">Sizing a database environment</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_open.html">Opening databases within the
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environment</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_error.html">Error support</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_db_config.html">DB_CONFIG configuration
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file</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_naming.html">File naming</a>
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</span>
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</dt>
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<dd>
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<dl>
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<dt>
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<span class="sect2">
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<a href="env_naming.html#idm140654538864576">Specifying file naming to Berkeley DB</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="env_naming.html#idm140654538873824">Filename resolution in Berkeley DB</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="env_naming.html#idm140654546493792">Examples</a>
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</span>
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</dt>
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</dl>
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</dd>
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<dt>
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<span class="sect1">
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<a href="env_region.html">Shared memory regions</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_security.html">Security</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_encrypt.html">Encryption</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_remote.html">Remote filesystems</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="env_faq.html">Environment FAQ</a>
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</span>
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</dt>
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</dl>
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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="env_intro"></a>Database environment introduction</h2>
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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 Berkeley DB environment is an encapsulation of one or more
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databases, log files and region files. Region files are the
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shared memory areas that contain information about the
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database environment such as memory pool cache pages. Only
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databases are byte-order independent and only database files
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can be moved between machines of different byte orders. Log
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files can be moved between machines of the same byte order.
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Region files are usually unique to a specific machine and
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potentially to a specific operating system release.
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</p>
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<p>
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The simplest way to administer a Berkeley DB application
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environment is to create a single <span class="bold"><strong>home</strong></span>
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directory that stores the files for the
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applications that will share the environment. The environment
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home directory must be created before any Berkeley DB
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applications are run. Berkeley DB itself never creates the
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environment home directory. The environment can then be
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identified by the name of that directory.
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</p>
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<p>
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An environment may be shared by any number of processes, as
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well as by any number of threads within those processes. It is
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possible for an environment to include resources from other
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directories on the system, and applications often choose to
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distribute resources to other directories or disks for
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performance or other reasons. However, by default, the
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databases, shared regions (the locking, logging, memory pool,
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and transaction shared memory areas) and log files will be
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stored in a single directory hierarchy.
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</p>
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<p>
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It is important to realize that all applications sharing a
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database environment implicitly trust each other. They have
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access to each other's data as it resides in the shared
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regions, and they will share resources such as buffer space
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and locks. At the same time, any applications using the same
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databases <span class="bold"><strong>must</strong></span> share an
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environment if consistency is to be maintained between
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them.
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</p>
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<p>
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For more information on the operations supported by the
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database environment handle, see the <a href="../api_reference/C/env.html#envlist" class="olink">Database Environments and Related
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Methods</a> section in the
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<em class="citetitle">Berkeley DB C API Reference Guide.</em>
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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="arch_utilities.html">Prev</a> </td>
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<td width="20%" align="center"> </td>
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<td width="40%" align="right"> <a accesskey="n" href="env_create.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">Supporting utilities </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"> Creating a database
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environment</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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