| Interface annotation? [message #387770] |
Fri, 08 May 2009 09:13  |
Eclipse User |
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Hi,
In toplink/eclipselink native there is this advanced feature, where you
can query on an interface.
For instance if Cat and Dog both implement a common interface, say
Lovable, but are mapped in different tables and don't even have a common
superclass you can send a ReadAllQuery(Lovable.class) and get both cats
and dogs.
Can I define this with annotations? I know it's not JPA standard, but I
looked in the JPA Extensions and found VariableOneToOneMapping, which is a
mapping to an interface. So I was wondering if one can annotate an
interface, maybe define its query keys in the annotation, and be able to
query on them. With EJBQL?
In the native project.xml it's something like this
<class-mapping-descriptor
xsi:type="relational-class-mapping-descriptor">
<class>pet.Lovable</class>
..
<query-keys>
<query-key name="sweetnessFactor" xsi:type="query-key"/>
..
</query-keys>
</class-mapping-descriptor>
<class-mapping-descriptor
xsi:type="relational-class-mapping-descriptor">
<class>pet.Cat</class>
..
<interfaces>
<interface>pet.Lovable</interface>
</interfaces>
</class-mapping-descriptor>
Thanx,
Ana
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