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| <div class="sect2"><!-- infolevel="all" infotype="General" --> |
| <h1>Mapped superclass</h1> |
| <p><a id="sthref83" name="sthref83"></a><a id="sthref84" name="sthref84"></a>An entity that extends a <span class="bold">Mapped Superclass</span> class inherits 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> |
| <p>Abstract or concrete classes</p> |
| </li> |
| </ul> |
| <p>A mapped superclass <span class="italic">cannot be</span>:</p> |
| <ul> |
| <li> |
| <p>Be queried or passed as an argument to Entity-Manager or Query operations</p> |
| </li> |
| <li> |
| <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="sthref85" name="sthref85"></a><a id="sthref86" name="sthref86"></a><a id="sthref87" name="sthref87"></a><a id="sthref88" name="sthref88"></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> |
| <li> |
| <p>Open the Java class in the <span class="gui-object-title">Project 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 open the Mapping Type Selection dialog.</p> |
| </li> |
| <li> |
| <p>Select <span class="bold">Mapped Superclass</span> and then <span class="bold">OK</span>.</p> |
| <div class="figure"><a id="sthref89" name="sthref89"></a> |
| <p class="titleinfigure">Mapping Type Selection Dialog (Mapped Superclass)</p> |
| <img src="img/mapping_type_selection_superclass.png" alt="The Mapping Type Selection dialog with Mapped Superclass selected." title="The Mapping Type Selection dialog with Mapped Superclass 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> |
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