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| <h1>Mapped superclass</h1> |
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| <p><a id="sthref90" name="sthref90"></a><a id="sthref91" name="sthref91"></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> |
| </li> |
| </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> |
| </li> |
| </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="sthref92" name="sthref92"></a><a id="sthref93" name="sthref93"></a><a id="sthref94" name="sthref94"></a><a id="sthref95" name="sthref95"></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> |
| <div class="figure"><a id="sthref96" name="sthref96"></a> |
| <p class="titleinfigure">Selecting Mapped Superclass Persistence</p> |
| <img src="img/persistence_view_mappedsprc.png" alt="Selecting embedded persistence on the JPA Details view." title="Selecting embedded persistence on the JPA Details view." /><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> |
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