I'm trying to figure out how i can create a Set that will generally contain 3 different types of the abstract class.

Submission
-------------
+getBatches() ISet

Batch : Absract
------------------


BatchtypeA : Batch
-----------------------

BatchtypeB : Batch
-----------------------

BatchtypeC : Batch
-----------------------

So with this setup i have a table with a discriminator for A B C and Abstract classes. This works fine.

I tried just simply adding in a Set Mapping
<set name="Batches" table="Batch">
<key column="submissionID" />
<one-to-many class="Batch" />
</set>

IT builds and runs however i get a null reference exception inside Nhibernate when it tries to save. and an ADOException saying "could not save object"

I Belive this should be possible but perhaps i am taking the wrong road to it.

Thanks for any help