Hibernate version:
Hibernate 3 under EJB3

All I want is to know if this is possible using the EJB3 over hibernate 3 and Jboss 4.0.4 GA.

I have a parent class

abstract class A{

Integer id;
attr A;
attr B;
}

class B extends A{

string aName;
attr C;
attr D;
}


I want to make aName in class B a part of the primary Key so the primary key in b will be (id -> pk,fk, aName,pk) I must enforce that no aName is repeated and I must index this field (so the field can't be nullable)

I ruled out the Single Table strategy. As I'm using POSTGRE SQL and it supports SQL UNION I really don't care if the strategy is JOINED or TABLE_PER_CLASS).

Please tell me if there is a way I can do this.