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<h1>Mapped superclass</h1>
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<p><a id="sthref90" name="sthref90"></a>An entities that extend a <span class="bold">Mapped Superclass</span> class inherit the persistent state and mapping information from a superclass. You should use a mapped superclass to define mapping information that is common to multiple entity classes.</p>
<p>A mapped superclass <span class="italic">can be</span>:</p>
<ul>
<li type="disc">
<p>Abstract or concrete classes</p>
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</ul>
<p>A mapped superclass <span class="italic">cannot be</span>:</p>
<ul>
<li type="disc">
<p>Be queried or passed as an argument to Entity-Manager or Query operations</p>
</li>
<li type="disc">
<p>Be the target of a persistent relationship</p>
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</ul>
<p>A mapped superclass does not have a defined database table. Instead, its mapping information is derived from its superclass. To override the mapping information for a specific subclass, use the <code>@AttributeOverride</code> annotation for that specific class.</p>
<p><a id="sthref91" name="sthref91"></a><a id="sthref92" name="sthref92"></a><a id="sthref93" name="sthref93"></a><a id="sthref94" name="sthref94"></a>A mapped superclass is identified by the <code>@MappedSuperclass</code> annotation.</p>
<p>Use this procedure to add Mapped Superclass persistence to an existing entity:</p>
<ol type="1" 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 <span class="gui-object-title">JPA Details</span> view, use the <span class="gui-object-action">Map As</span> drop-list to select <span class="gui-object-action">Mapped Superclass</span>.</p>
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<p class="titleinfigure">Selecting Mapped Superclass Persistence</p>
<img src="img/persistence_view_mappedsprc.png" alt="Selecting embedded persistence on the Persistence Properties view." title="Selecting embedded persistence on the Persistence Properties view." /><br /></div>
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<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></div>
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