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HTML
187 lines
8 KiB
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>Developing a JE Collections Application</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 Java Edition Collections Tutorial" />
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<link rel="up" href="intro.html" title="Chapter 1. Introduction" />
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<link rel="prev" href="intro.html" title="Chapter 1. Introduction" />
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<link rel="next" href="tutorialintroduction.html" title="Tutorial Introduction" />
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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 12.2.7.5</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">Developing a JE Collections Application</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="intro.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 1.
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Introduction
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="tutorialintroduction.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="developing"></a>Developing a JE Collections Application</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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There are several important choices to make when developing an
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application using the JE JE Collections API.
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</p>
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<div class="orderedlist">
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<ol type="1">
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<li>
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<p>
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Choose the Format for Keys and Values
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</p>
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<p>
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For each database you may choose a binding format for the keys
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and values. For example, the tuple format is useful for keys
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because it has a deterministic sort order. The serial format is
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useful for values if you want to store arbitrary Java objects. In
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some cases a custom format may be appropriate. For details on
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choosing a binding format see
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<a class="xref" href="collectionOverview.html#UsingDataBindings" title="Using Data Bindings">
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Using Data Bindings
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</a>.
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</p>
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</li>
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<li>
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<p>
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Choose the Binding for Keys and Values
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</p>
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<p>
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With the serial data format you do not have to create a binding
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for each Java class that is stored since Java serialization is
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used. But for other formats a binding must be defined that
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translates between stored byte arrays and Java objects. For details
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see
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<a class="xref" href="collectionOverview.html#UsingDataBindings" title="Using Data Bindings">
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Using Data Bindings
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</a>.
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</p>
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</li>
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<li>
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<p>
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Choose Secondary Indices<span> and Foreign Key Indices</span>
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</p>
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<p>
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Any database that has unique keys may have any number of
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secondary indices. A secondary index has keys that are derived from
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data values in the primary database. This allows lookup and
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iteration of objects in the database by its index keys.
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<span>
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A foreign key index is a special type of secondary index where the index keys
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are also the primary keys of another primary database.
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</span>
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For each index you must define how the index keys are derived from the data
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values using a
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<span>
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<a class="ulink" href="../../java/com/sleepycat/je/SecondaryKeyCreator.html" target="_top">SecondaryKeyCreator</a>.
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</span>
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For details see the
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<span>
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<a class="ulink" href="../../java/com/sleepycat/je/SecondaryDatabase.html" target="_top">SecondaryDatabase</a>,
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</span>
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<a class="ulink" href="../../java/com/sleepycat/je/SecondaryConfig.html" target="_top">SecondaryConfig</a>
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and
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<a class="ulink" href="../../java/com/sleepycat/je/SecondaryKeyCreator.html" target="_top">SecondaryKeyCreator</a>
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classes.
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</p>
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</li>
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<li>
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<p>
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Choose the Collection Interface for each Database
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</p>
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<p>
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The standard Java Collection interfaces are used for accessing
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databases and secondary indices. The Map and Set interfaces may be
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used for any type of database. The Iterator interface is used
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through the Set interfaces. For more information on the collection
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interfaces see
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<a class="xref" href="UsingStoredCollections.html" title="Using Stored Collections">
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Using Stored Collections
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</a>.
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</p>
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</li>
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</ol>
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</div>
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<p>
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Any number of bindings and collections may be created for the
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same database. This allows multiple views of the same stored data.
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For example, a data store may be viewed as a Map of keys to values,
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a Set of keys, or a Collection of values. String values, for
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example, may be used with the built-in binding to the String class,
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or with a custom binding to another class that represents the
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string values differently.
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</p>
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<p>
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It is sometimes desirable to use a Java class that encapsulates
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both a data key and a data value. For example, a Part object might
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contain both the part number (key) and the part name (value). Using
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the JE JE Collections API this type of object is called an
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"entity". An entity binding is used to translate between the Java
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object and the stored data key and value. Entity bindings may be
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used with all Collection types.
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</p>
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<p>
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Please be aware that the provided JE JE Collections API collection classes
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do not conform completely to the interface contracts
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defined in the <code class="literal">java.util</code> package. For example, all
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iterators must be explicitly closed and the <code class="methodname">size()</code>
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method is not available. The differences between the JE JE Collections API
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collections and the standard Java collections are
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documented in
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<a class="xref" href="UsingStoredCollections.html#StoredVersusStandardCollections" title="Stored Collections Versus Standard Java Collections">
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Stored Collections Versus Standard Java Collections
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</a>.
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</p>
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</div>
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<div class="navfooter">
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<hr />
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|
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<table width="100%" summary="Navigation footer">
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|||
|
|
<tr>
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|||
|
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<td width="40%" align="left"><a accesskey="p" href="intro.html">Prev</a> </td>
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|||
|
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<td width="20%" align="center">
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|||
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<a accesskey="u" href="intro.html">Up</a>
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|||
|
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</td>
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|||
|
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<td width="40%" align="right"> <a accesskey="n" href="tutorialintroduction.html">Next</a></td>
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|||
|
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</tr>
|
|||
|
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<tr>
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|||
|
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<td width="40%" align="left" valign="top">Chapter 1.
|
|||
|
|
Introduction
|
|||
|
|
</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"> Tutorial Introduction</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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