In <class> tag, there is an attribute named polymorphism. I read online docs but not understant the different well. May somebody explain it detail or give an example?

It has to do with Hibernate's support for "polymorphic" queries. Say you have a class named Person mapped plus two others named Student and Instructor both of which extend from Person. Further, say you've mapped Student with explicit polymorphism and Instructor with implicit. In that case any queries looking for the Person class would return back not only all Person objects matching the criteria, but also all Instructors as well since it was mapped with implicit polymorphism.

Basically, explict polymorphism tells Hibernate not to return these instances during a query unless that class is explicitly named in the query, not just because one of its superclasses was named.

HTH

Suppose I have a class hierachy using joined-subclass method; is there a way to mimic the polymorphism=explicit feature ? i.e. I don't want some subclasses to ever be returned in queries. The reason I'm asking is because the <joined-subclass> tag does not have the polymorphism attribute as in the class tag.

Merci beaucoup

alistair