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    <title>Chapter��7.��Databases</title>
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            <h2 class="title"><a id="DB"></a>Chapter��7.��Databases</h2>
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        <p>
          <b>Table of Contents</b>
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        <dl>
          <dt>
            <span class="sect1">
              <a href="DB.html#DBOpen">Opening Databases</a>
            </span>
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            <span class="sect1">
              <a href="coredbclose.html">Closing Databases</a>
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              <a href="DBConfig.html">Database Properties</a>
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            <span class="sect1">
              <a href="DBAdmin.html">Administrative Methods</a>
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            <span class="sect1">
              <a href="dbErrorReporting.html">Error Reporting Functions</a>
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            <span class="sect1">
              <a href="CoreEnvUsage.html">Managing Databases in Environments</a>
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              <a href="CoreJavaUsage.html">Database Example</a>
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      <p>In Berkeley DB, a database is a collection of <span class="emphasis"><em>records</em></span>. Records,
  in turn, consist of key/data pairings.
  </p>
      <p>
	Conceptually, you can think of a
		<tt class="classname">Database</tt>

	as containing a two-column table where column 1 contains a key and column 2
	contains data.  Both the key and the data are managed using
		<tt class="classname">DatabaseEntry</tt>


		<span>class instances</span>

	(see <a href="DBEntry.html">Database Records</a> for details on this
	    <span>class</span>
	    ).
	So, fundamentally, using a DB
		<tt class="classname">Database</tt>

	involves putting, getting, and deleting database records, which in turns involves efficiently
	managing information
		<span>encapsulated by </span>


		<tt class="classname">DatabaseEntry</tt>


		<span>objects.</span>

	The next several chapters of this book are dedicated to those activities.
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              <h2 class="title" style="clear: both"><a id="DBOpen"></a>Opening Databases</h2>
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        <p>
        You open a database by instantiating a <tt class="classname">Database</tt>
        object.
    </p>
        <p>
		Note that by default, DB does not create databases if they do not already exist.
		To override this behavior, set the <a href="DBConfig.html" title="Database Properties">creation property</a> to true.
	</p>
        <p>
        The following code fragment illustrates a database open:

    </p>
        <a id="java_db1"></a>
        <pre class="programlisting">package db.GettingStarted;

import com.sleepycat.db.DatabaseException;
import com.sleepycat.db.Database;
import com.sleepycat.db.DatabaseConfig;

import java.io.FileNotFoundException;
...

Database myDatabase = null;

...

try {
    // Open the database. Create it if it does not already exist.
    DatabaseConfig dbConfig = new DatabaseConfig();
    dbConfig.setAllowCreate(true);
    myDatabase = new Database ("sampleDatabase.db",
                               null,
                               dbConfig);
} catch (DatabaseException dbe) {
    // Exception handling goes here
} catch (FileNotFoundException fnfe) {
    // Exception handling goes here
}</pre>
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