blob: d3c26442fb3e0f079160fbbeb1626329f6ce2369 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<!-- Run date = May 21, 2008 14:42:04 -->
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" />
<title>Entity</title>
<meta http-equiv="Content-Style-Type" content="text/css" />
<meta http-equiv="Content-Script-Type" content="text/javascript" />
<meta name="generator" content="Oracle DARB XHTML Converter (Mode = ohj/ohw) - Version 5.0" />
<meta name="date" content="2005-07-10T12:57:20+08:00" />
<meta name="robots" content="noarchive" />
<meta name="doctitle" content="Entity" />
<meta name="relnum" content="Release 2.0" />
<meta name="copyright" content="Copyright (c) 2000, 2008 oracle . All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html. Contributors: Oracle - initial API and implementation" />
<link rel="copyright" href="dcommon/html/cpyr.htm" title="Copyright" type="text/html" />
<link rel="stylesheet" href="dcommon/css/blafdoc.css" title="Oracle BLAFDoc" type="text/css" />
<link rel="start" href="../../index.htm" title="Home" type="text/html" />
<link rel="contents" href="toc.htm" title="Contents" type="text/html" />
</head>
<body>
<p><a id="BABGBIEE" name="BABGBIEE"></a></p>
<div class="sect2"><!-- infolevel="all" infotype="General" -->
<h1>Entity</h1>
<p><a id="sthref55" name="sthref55"></a><a id="sthref56" name="sthref56"></a><a id="sthref57" name="sthref57"></a><a id="sthref58" name="sthref58"></a>An <span class="bold">Entity</span> is a persistent domain object.</p>
<p>An entity <span class="italic">can be</span>:</p>
<ul>
<li>
<p>Abstract or concrete classes. Entities may also extend non-entity classes as well as entity classes, and non-entity classes may extend entity classes.</p>
</li>
</ul>
<p>An entity <span class="italic">must have</span>:</p>
<ul>
<li>
<p>A no-arg constructor (public or protected); the entity class may have other constructors as well.</p>
</li>
</ul>
<p><a id="sthref59" name="sthref59"></a><a id="sthref60" name="sthref60"></a><a id="sthref61" name="sthref61"></a>Each persistent entity must be mapped to a database table and contain a primary key. Persistent entities are identified by the <code>@Entity</code> annotation.</p>
<p>Use this procedure to add persistence to an existing entity:</p>
<ol start="1">
<li>
<p>Open the Java class in the <span class="gui-object-title">Package Explorer.</span></p>
</li>
<li>
<p>Select the class in the JPA Structure view.</p>
</li>
<li>
<p>In the JPA Details view, click the mapping type hyperlink to access the Mapping Type Selection dialog. In the following figure, clicking <span class="italic">entity</span> invokes the dialog from the JPA Details View.</p>
<div class="figure"><a id="sthref62" name="sthref62"></a>
<p class="titleinfigure">The Mapping Type Hyperlink</p>
<img src="img/mapped_entity_type_link.png" alt="The JPA Details view for an entity showing the mapping type hyperlink." title="The JPA Details view for an entity showing the mapping type hyperlink." /><br /></div>
<!-- class="figure" -->
<div align="center">
<div class="inftblnotealso"><br />
<table class="NoteAlso oac_no_warn" summary="" cellpadding="3" cellspacing="0">
<tbody>
<tr>
<td align="left">
<p class="notep1">Tip:</p>
You can also change add persistence for an entity by right-clicking the class in the JPA Structure View and then clicking <span class="bold">Map As > Entity</span>.</td>
</tr>
</tbody>
</table>
<br /></div>
<!-- class="inftblnotealso" --></div>
</li>
<li>
<p>Select <span class="bold">Entity</span> from the Mapping Type Selection dialog and then click <span class="bold">OK</span>.</p>
<div class="figure"><a id="sthref63" name="sthref63"></a>
<p class="titleinfigure">The Mapping Type Selection Dialog</p>
<img src="img/mapping_type_selection_entity.png" alt="The Mapping Type selection dialog with Enity selected." title="The Mapping Type selection dialog with Enity selected." /><br /></div>
<!-- class="figure" --></li>
<li>
<p>Complete the remaining <a href="ref_persistence_prop_view.htm#BABFAEBB">JPA Details view (for entities)</a>.</p>
</li>
</ol>
<p> </p>
<img src="img/ngrelt.png" alt="Related tasks" title="Related tasks" /><br />
<br />
<a href="task_add_persistence.htm#BABHICAI">Adding persistence to a class</a><br />
<a href="task_additonal_tables.htm#CIHGBIEI">Specifying additional tables</a><br />
<a href="task_inheritance.htm#CIHCCCJD">Specifying entity inheritance</a><br /></div>
<!-- class="sect2" -->
<!-- Start Footer -->
<div class="footer">
<table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%">
<tr>
<td align="left" width="86%"><a href="dcommon/html/cpyr.htm"><span class="copyrightlogo">Copyright © 2006, 2008, Oracle. All rights reserved.</span></a></td>
</tr>
</table>
</div>
<!-- class="footer" -->
</body>
</html>
|
