Hibernate version:
3.0.5

Full stack trace of any exception that occurs:
Unknown entity: com.semagix.core.extraction.model.TransientEntity

Name and version of the database you are using:
hsqldb 1.8.0

I have what i think is probably an easy problem to fix, but I'm not sure of the best approach. I have a mapped class Entity in a library, and i've subclassed it with an unmapped class for some extra data. I'd like to be able to use them without worrying about the type (i.e. reference both as an Entity object ala instanceof), but when i persist, I only want to persist the Entity object, not any of the TransientEntity object's properties. I get the above stack trace when i try to saveOrUpdate the TransientEntity object, eventhough it's a subclass of an Entity. Is there a way to save it w/o mapping it, short of a deep copy?

Thanks,
Jason

Some suggestions:

What if you just cast it to the superclass? Probably won't work, but worth a try.

Or, make a <subclass> mapping for TransientEntity that has nothing in it. It only inherits Entity mappings. Of course you would need to declare a discriminator in the Entity mapping and a discriminator value in TransientEntity mapping. This is the table-per-class-hierarchy strategy. Of course you would get TransientEntities when you retrieve from the database.

Or, if Entity is an abstract class why not just associate the mapping with TransientEntity. It doesn't matter that you don't map TransientEntity's variables. This is the table-per-concrete-class strategy. Once again you would be retrieving TransientEntities.

Entity is in a library i am importing. I want to manipulate it with some extra markup for processing, so i subclassed it with some additional unpersisted params. I'd prefer not to edit the mappings on the superclass to add a descriminator, so i tried this:

session.saveOrUpdate("com.semagix.ontology.model.Entity", obj);

where obj is a TransientEntity. Seems to work great!

Any of the hibernate team see a problem with this strategy?

Jason