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
|
<!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 = January 22, 2008 9:11:15 -->
<meta name="OAC_IGNORE_SKIP_NAV" content="true" />
<title>Create one-to-one mappings</title>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" />
<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="Create one-to-one mappings" />
<meta name="relnum" content="M5 - Release 2.0.0" />
<meta name="partnum" content="" />
<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="BABGBGHF" name="BABGBGHF"></a></p>
<div class="sect3"><!-- infolevel="all" infotype="General" -->
<h1>Create one-to-one mappings</h1>
<p>Use a <span class="bold">One-to-One Mapping</span> to define a relationship from an attribute to another class, with one-to-one multiplicity to a database column. In the <a href="getting_started006.htm#BABIDCBA">Tutorial Object Model</a>, the <span class="bold">address</span> field of the <span class="bold">Employee</span> class has a one-to-one relationship to the <span class="bold">Address</span> class; each employee may have a single address.</p>
<ol start="1">
<li>
<p>Select the <span class="bold">Employee</span> entity in the Package Explorer view.</p>
</li>
<li>
<p>In the <a href="ref_persistence_outline.htm#BABEGGFE">JPA Structure view</a>, select the <span class="bold">address</span> field of the <span class="bold">Employee</span> entity. The <a href="ref_persistence_map_view.htm#BABIFBAF">JPA Details view (for attributes)</a> displays the properties for the field.</p>
</li>
<li>
<p>In the <span class="gui-object-title">Map As</span> field, select <span class="gui-object-action">One-to-One</span>.</p>
<div class="figure"><a id="sthref32" name="sthref32"></a>
<p class="titleinfigure">One-to-one Mapping for address</p>
<img src="img/persistence_view_onetoone.png" alt="JPA Details view for the address field." title="JPA Details view for the address field." /><br /></div>
<!-- class="figure" --></li>
<li>
<p>For the Target Entity, click <span class="bold">Browse</span> and select the <span class="bold">Address</span> persistent entity. Dali adds the <code>@OneToOne(targetEntity=dali.tutorial.model.Address.class)</code> entity to the class.</p>
<p>Leave the other fields with their default values.</p>
</li>
<li>
<p>Select the <span class="bold">Override Default</span> option to specify the relationship between the Employee and Address entities. Because you had to explicitly define the ID field for the Address entity in its ID mapping, you will need to edit the default join relationship.</p>
</li>
<li>
<p>Select the <span class="bold">address_ADDRESS_ID -> ADDRESS_ID</span> relationship in the <span class="gui-object-title">Join Columns</span> area and click <span class="bold">Edit</span>.</p>
</li>
<li>
<p>In the Edit Join Column dialog, select the following options and click <span class="bold">OK</span>.</p>
<ul>
<li>
<p>Name: <span class="bold">ADDR_ID</span> (from the EMPLOYEE table)</p>
</li>
<li>
<p>Referenced Column Name: <span class="bold">ADDRESS_ID</span> (from the ADDRESS table)</p>
</li>
</ul>
<div class="figure"><a id="sthref33" name="sthref33"></a>
<p class="titleinfigure">Editing Join Column for Address Mapping</p>
<img src="img/edit_join_column_dialog.png" alt="Edit Join Column dialog for the address 1:1 mapping." title="Edit Join Column dialog for the address 1:1 mapping." /><br /></div>
<!-- class="figure" --></li>
</ol>
<p>In the JPA Structure, the <span class="bold">address</span> field is identified as a one-to-one mapping, as shown in the following figure:</p>
<div class="figure"><a id="sthref34" name="sthref34"></a>
<p class="titleinfigure">JPA Structure for Employee Entity</p>
<img src="img/persistence_outline_address.png" alt="The address attribute of the Employee entity in the JPA Structure view." title="The address attribute of the Employee entity in the JPA Structure view." /><br /></div>
<!-- class="figure" -->
<p>Next, you will <a href="getting_started017.htm#BABBEHEG">Create one-to-many mappings</a>.</p>
</div>
<!-- class="sect3" -->
<!-- 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>
|
