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From conflue...@apache.org
Subject [CONF] Apache Cayenne > Is Inheritance Supported
Date Sat, 26 Jun 2010 16:12:00 GMT
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    <h2><a href="https://cwiki.apache.org/confluence/display/CAY/Is+Inheritance+Supported">Is
Inheritance Supported</a></h2>
    <h4>Page <b>edited</b> by             <a href="https://cwiki.apache.org/confluence/display/~andrus">Andrus
Adamchik</a>
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                         <h4>Changes (2)</h4>
                                 
    
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<br>Cayenne supports *single-table inheritance* (flat, table-per-class-hierarchy) natively.
<br> <br>*Vertical inheritance* (table-per-subclass) is being discussed and worked
on.   As a workaround, it&#39;s possible to simulate much of vertical inheritance using
templating and composite DataObjects.  See [CompositeVerticalInheritance] for details.  However,
there&#39;s an inability to query across all tables sharing this custom superclass.  There
may also be issues with invalidating or refetching. <br> <br>*Horizontal Inheritance*
(table-per-concrete-class) is not currently supported.  In [this message|http://www.objectstyle.org/cayenne/lists/cayenne-devel/2005/05/0003.html],
<br> Randy Leonard suggested that horizontal inheritance could be simulated by creating
a subclass of CayenneDataObject which contained access to shared properties, and having data
objects inherit from this class.  Again there&#39;s an inability to query across all tables
sharing this custom superclass.  <br></td></tr>
            <tr><td class="diff-added-lines" style="background-color: #dfd;">Cayenne
supports single-table and vertical inheritance mapping. <br></td></tr>
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</div>                            <h4>Full Content</h4>
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        <p>Cayenne supports single-table and vertical inheritance mapping.</p>
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