Question on Mapping

Can any body tell me why <generator class> used and what is the purpose of using that?

The hibernate documentation can (assuming it is Hibernate you are asking about, and not some other ORM).

have a look at the hibernate (assuming you talk about hibernate since you did not even bother to write what ORM you talk about) docu or use gooogle.

if you do not find anything then i'm happy to help....

pascal

Paul: are you reading my mind ? :-)

pascal