I am using Hibernate 2.1.6 and the Table Per Subclass (joined subclass) method of inheritance mapping. If I have the following inheritance hierarchy ...

B -> Base Class
C -> Inherits from B
D -> Inherits from B

I can retrieve all instances by using HQL of the form ...

"from B as b"

However, if I attempt to do something like ...

"from B as b where b.class = C"

I get no results back, even though I have instances of both C and D.

The query compiles fine and executes. Does the above work with the Table Per Subclass method of inheritance?

I also tried supplying the "polymorphic association" as described in Chapter 8 of the docs. Ex.

<many-to-one name="base"
column="b"
class="B"/>

But it is not clear how this association gets set. Can someone please explain the reason for this association? I could not provide any explanatory text in the docs.

Thanks,
Brian

Joined-subclasses don't have a user defined discriminator value. Hibernate uses -1 for null, 0 for the base class, etc.. I am going to write a JIRA issue for this.
Anyway: why don't you simply query "from C" ?
The query "from B b where b.class=1" probably also works.

Yes, I had just thought that the joined-subclasses could be identified via this class name, since Hibernate obviously knows about it. Thanks for the tip on the integer. That indeed works.

Do you know what the polymorphic association in the docs is used for?

Thanks,
Brian

No.