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[Andromdaplugins-cvs] CVS update: cartridges/andromda-ejb3/src/site/xdoc howto4.xml
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From: Vance K. <va...@us...> - 2006-02-06 04:22:34
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User: vancek
Date: 06/02/05 20:22:26
Added: andromda-ejb3/src/site/xdoc howto4.xml
Log:
initial revision
Revision Changes Path
1.1 cartridges/andromda-ejb3/src/site/xdoc/howto4.xml
Index: howto4.xml
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<?xml version="1.0" encoding="iso-8859-1"?>
<document>
<properties>
<author email="va...@us...">Vance Karimi</author>
<title>AndroMDA - EJB3 - HowTo Composite Primary Key</title>
</properties>
<body>
<section name="Composite Primary Key">
<p>
In some cases, you may want to define a composite primary key, rather than a simple primary key.
A composite primary key must correspond to two or more persistent fields or properties. The
EJB3 cartridge allow the creation of a composite primary key class to satisfy this requirement.
</p>
<p>
To map two or more attributes of an entity POJO as a property of a composite primary key, simply
model the <![CDATA[<<Identifier>>]]> stereotype on the corresdponding attributes in the entity.
The order of the primary keys is defined by the order of the attribute identifiers in the entity.
</p>
<p>
The following example introduces a composite primary key for the Car entity.
</p>
<p>
<img src="images/org/andromda/test/4/a/uml.gif"/>
</p>
<p>
<ul>
<li class="gen">Auto-generated source that does not need manual editing</li>
<li class="impl">Auto-generated source that should be edited manually</li>
<li class="changed">File that is affected by the modifications applied in this section</li>
</ul>
</p>
<p>
<ul>
<li class="gen"><a class="changed" href="src/org/andromda/test/howto4/a/CarEmbeddable.java"><code>CarEmbeddable.java</code></a></li>
<li class="impl"><a class="changed" href="src/org/andromda/test/howto4/a/Car.java"><code>Car.java</code></a></li>
<li class="gen"><a class="changed" href="src/org/andromda/test/howto4/a/CarPK.java"><code>CarPK.java</code></a></li>
<li class="gen"><a class="changed" href="src/org/andromda/test/howto4/a/PersonEmbeddable.java"><code>PersonEmbeddable.java</code></a></li>
<li class="impl"><a class="changed" href="src/org/andromda/test/howto4/a/Person.java"><code>Person.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/ServiceLocator.java"><code>ServiceLocator.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto4/a/RentalServiceBean.java"><code>RentalServiceBean.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto4/a/RentalServiceRemote.java"><code>RentalServiceRemote.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto4/a/RentalServiceDelegate.java"><code>RentalServiceDelegate.java</code></a></li>
<li class="impl"><a href="src/org/andromda/test/howto4/a/RentalServiceBeanImpl.java"><code>RentalServiceBeanImpl.java</code></a></li>
</ul>
</p>
<p>
The EJB3 cartridge represents a composite primary key as an embeddable class, implements
<code>Serializable</code> and defines the <code>equals</code> and <code>hashCode</code> methods.
The <code>CarPK</code> embeddable composite primary key class has the
<code>@javax.persistence.Embeddable</code> annotation. The <code>CarEmbeddable</code> class
contains the corresponding <code>@javax.persistence.EmbeddedId</code> annotation on the
composite primary key getter. Notice how the <code>@javax.persistence.AttributeOverrides</code>
annotation is used to map the primary key attributes to the relational database columns.
</p>
<p>
The following example illustrates the effect of having a composite primary key on the inverse
side of a relationship. What's important here is the <code>@javax.persistence.JoinColumns</code>
annotation on <code>getOwner()</code> in <code>CarEmbeddable.java</code>. Because
<code>Person</code> has a composite primary key, the foreign key on Many-To-One owning side
has to know about this.
</p>
<p>
<img src="images/org/andromda/test/4/b/uml.gif"/>
</p>
<p>
<ul>
<li class="gen">Auto-generated source that does not need manual editing</li>
<li class="impl">Auto-generated source that should be edited manually</li>
<li class="changed">File that is affected by the modifications applied in this section</li>
</ul>
</p>
<p>
<ul>
<li class="gen"><a class="changed" href="src/org/andromda/test/howto4/b/CarEmbeddable.java"><code>CarEmbeddable.java</code></a></li>
<li class="impl"><a class="changed" href="src/org/andromda/test/howto4/b/Car.java"><code>Car.java</code></a></li>
<li class="gen"><a class="changed" href="src/org/andromda/test/howto4/b/PersonEmbeddable.java"><code>PersonEmbeddable.java</code></a></li>
<li class="impl"><a class="changed" href="src/org/andromda/test/howto4/b/Person.java"><code>Person.java</code></a></li>
<li class="gen"><a class="changed" href="src/org/andromda/test/howto4/b/PersonPK.java"><code>PersonPK.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/ServiceLocator.java"><code>ServiceLocator.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto4/b/RentalServiceBean.java"><code>RentalServiceBean.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto4/b/RentalServiceRemote.java"><code>RentalServiceRemote.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto4/b/RentalServiceDelegate.java"><code>RentalServiceDelegate.java</code></a></li>
<li class="impl"><a href="src/org/andromda/test/howto4/b/RentalServiceBeanImpl.java"><code>RentalServiceBeanImpl.java</code></a></li>
</ul>
</p>
<p>
Currently, the EJB3 cartridge will disable the findByPrimaryKey generic finder for an entity
with a composite primary key.
</p>
</section>
<section name="Next">
<p>
As promised we'll learn how to model enumerations, click <a href="howto5.html">here</a>.
</p>
</section>
</body>
</document>
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