Question

we have a hibernate mapping file (hbm.xml file) that maps a part of our domain to the database. This part contains a inheritance hierarchy. I.e. we have a parent class ‘Parent’ and several subclasses ‘Child1’, ‘Child2’, …

Because of the structure of the hibernate mapping file the child classes are located within the parents <class> XML tag as <joined-subclass>.

Since this mapping file becomes larger and larger we now want to split it. Is there a way to have a mapping file for each subclass?

Answer 1

The tag in the new XML:

<joined-subclass />

Or

<hibernate-mapping>
 <subclass name="DomesticCat" extends="Cat" discriminator-value="D">
      <property name="name" type="string"/>
 </subclass>
 </hibernate-mapping>

Extracted from the hibernate site:

It is possible to define subclass, union-subclass, and joined-subclass mappings in separate mapping documents directly.

Ref: http://docs.jboss.org/hibernate/core/3.3/reference/en/html/inheritance.html

Udo