Hi

I have an inheritance hierarchy mapped using table per subclass. Occasionally it is necessary to modify an instance so that it is a different class and persist this change.

So for example if we had a super class of Cat, which was subclassed by DomesticCat and FeralCat, mapped to three tables, I would need to be able to change a DomesticCat into a FeralCat, deleting a row from the domestic table and inserting one to the feral table.

Is there any way that this can be done through NHibernate?

Many thanks

Alex

Since it is not possible in .NET to simply transform an object from one class to another, it isn't possible in NH either. A better way to describe this would be the Role pattern.

Yes, the Role pattern would be a much better way to go about things.

Is it possible to implement component inheritence or would my roles have to be entity classes?

No, they do have to be entity classes. I think this is because components are analogous to value-types (structs).