I've got a mapping question, related to NHibernate 1.2.

Say I have TableA associated with ClassA and TableB associated with ClassB.

The relationship between ClassA and ClassB is one to one but for various reasons I can't give the two tables the same primary key value so I use <many-to-one unique="true".../> and so the primary key of TableB becomes a foreign key in TableA.

At some point I realise my design is flawed and ClassB should reference ClassA.

My question is thus can I do this without changing my database design?

The only way I can see to do it is to change things around so that the primary key of TableA becomes a foreign key in TableB.