2 x one-or-none-to-many



What is the best way to map this relatationship in EJB/database

EntityA 0-1 -------- 1 EntityB 1 --------- 0-1 EntityC

Where EntityB always has either 1 EntityA or 1 EntityC, never both, never
none.
They need to be bidirectional.

Thanks,
Mike W


.