I have the following parent/child relations:



Relations from top to bottom are all one-to-many. A has many Bs, A has many Cs, and both B and C have many Ds. D basically implements a many-to-many between B and C.

All associations are bi-directional. For all one-to-many set mappings, I have cascade="all-delete-orphan". For all many-to-one mappings, I have no cascade defined and not-null="true". In other words, all children must have a parent, and all operations cascade from parents to children.

The problem is I can't create a simple four object graph and save it. When I call saveOrUpdate on an object of ClassA, I get the following exception:



I assume this happens because Hibernate tries to persist the ClassD object before the ClassC object. How can I make this work? Isn't Hibernate supposed to correctly order saves so this doesn't happen? I am using version 2.1.6.

Thanks.