Import BSDDB 4.7.25 (as of svn r89086)
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Zachary Ware
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docs/gsg/JAVA/DBAdmin.html
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124
docs/gsg/JAVA/DBAdmin.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>Administrative Methods</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 V1.62.4" />
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<link rel="home" href="index.html" title="Getting Started with Berkeley DB" />
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<link rel="up" href="DB.html" title="Chapter 7. Databases" />
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<link rel="previous" href="DBConfig.html" title="Database Properties" />
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<link rel="next" href="dbErrorReporting.html" title="Error Reporting Functions" />
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</head>
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<body>
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<div class="navheader">
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">Administrative Methods</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="DBConfig.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 7. Databases</th>
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<td width="20%" align="right"> <a accesskey="n" href="dbErrorReporting.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="DBAdmin"></a>Administrative Methods</h2>
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</div>
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</div>
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<div></div>
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</div>
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<p>
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Both the <tt class="classname">Environment</tt> and
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<tt class="classname">Database</tt> classes provide methods that are useful
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for manipulating databases. These methods are:
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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>
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<tt class="methodname">Database.getDatabaseName()</tt>
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</p>
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<p>Returns the database's name.</p>
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<a id="je_db3.1"></a>
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<pre class="programlisting">String dbName = myDatabase.getDatabaseName();</pre>
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</li>
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<li>
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<p>
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<tt class="methodname">Database.rename()</tt>
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</p>
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<p>
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Renames the specified database. If no value is given for the
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<i class="parameter"><tt>database</tt></i> parameter, then the entire file
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referenced by this method is renamed.
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</p>
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<p>
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Never rename a database that has handles opened for it. Never rename a file that
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contains databases with opened handles.
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</p>
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<a id="java_db9"></a>
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<pre class="programlisting">import java.io.FileNotFoundException;
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...
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myDatabase.close();
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try {
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myDatabase.rename("mydb.db", // Database file to rename
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null, // Database to rename. Not used so
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// the entire file is renamed.
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"newdb.db", // New name to use.
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null); // DatabaseConfig object.
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// None provided.
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} catch (FileNotFoundException fnfe) {
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// Exception handling goes here
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}</pre>
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</li>
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<li>
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<p>
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<tt class="methodname">Environment.truncateDatabase()</tt>
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</p>
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<p>
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Deletes every record in the database and optionally returns the
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number of records that were deleted. Note that it is much less
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expensive to truncate a database without counting the number of
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records deleted than it is to truncate and count.
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</p>
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<a id="je_db5"></a>
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<pre class="programlisting">int numDiscarded =
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myEnv.truncate(null, // txn handle
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myDatabase.getDatabaseName(), // database name
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true); // If true, then the
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// number of records
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// deleted are counted.
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System.out.println("Discarded " + numDiscarded +
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" records from database " +
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myDatabase.getDatabaseName()); </pre>
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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 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="DBConfig.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="dbErrorReporting.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">Database Properties </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"> Error Reporting Functions</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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