Hello Thomas, > -----Original Message----- > From: Thomas Mahler [mailto:[EMAIL PROTECTED]
> > Suppose you have three class A, B, C. Suppose > > that both A and B have a collection of C. Suppose > > furthermore that every C instance is in exactly > > one of these collections. > > > > When I map this to a relational database, I might want > > to have four tables A, B, CA, CB, such that > > CA contains those C instances that are associated to an > > A instances (and analogously for B instead of A). > On the logical level it does not matter if a foreign key to C "comes > from" A or B. But in this case, I need a foreign key inside table C to table A or B, because classes A and B have a collection of C. It is like a 1-n relation from (A union B) to C. Can I have declare a reference in OJB in case A and B have no common super class? Olli --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
