Hi,

I have a class hierarchy. The superclass in Person. It has a subclass Lodger which has a subclass Alumni.

When a lodger move out, he becomes an alumni. An alumni can come back and move in again, then he becomes a lodger. I mapped the hierarchy with a discriminator and everythings work fine.

When I want to change a lodger to an alumni or contrary, I have to change the discriminator from "l" to "a" respectively from "a" to "l".

Is there a simple way to achieve this?

IMO this is a bad use for inheritance. Subclasses reflect a specialization of their superclass and in this case you've got a single entity that has multiple states. I'd consider factoring out the extra information on that sub-subclass and storing it in an optional many-to-one associated entity. This way when the status changes you can remove the extra info and change a flag.

Sorry for not answering your initial question -- but think of how this could work in Java (it can't; you can't just make some object into another).

-Chris

Hi Chris,

thank you for your answer.

Then I will try it in the way you described.

Greetings,

Christopher