I have a base class and two sub-classes mapped using the table-per-class strategy. The table is being loaded from an external (i.e. non-Hibernate) loader, and I then instantiate the classes using Hibernate.

My question is, in the external loader, what do I set the discriminator value to if I want to specify instances of the base class?

Each subclass has it's own discriminator value. Will NULL indicate an instance of the base class?

-Mitch

You can set discriminator-value for your class element.

Do you mean set a discriminator value within my base class definition, but outside of any <subclass/> elements? (i.e. at the same level as the <descriminator/> tag itself?)

No, set the discriminator-value of your class element. http://www.hibernate.org/hib_docs/reference/html/or-mapping.html#or-mapping-s1-3