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Hibernate version: 3.0

Firstly I would like to thank anyone in advance for any help they might provide.

Mine is a simple question. I have been using Hibernate for at least two year and I have used its inheritance capability in many projects. I find myself wanting to implement a multi level interitence tree... for example

animal -> bird -> sparrow

However I can not find an example of how to implement this. In the past I have used joined-subclass and from the 3.0 dtd I can see that you can embedded joined-subclasses. However I have no idea what is the best way to handle the primary key, or in fact that I am barking up the worng tree all together.

Any help would be appreciated.

Thanks Lee

Yes, the idea you have is right you can embed the <joined-subclass> again in a <joined-subclass> this will work for multi-level inheritance.

If you have a discriminator in your table then you can even go with <subclass> using discrimator-column and discriminator-value, this works.