Hello,

I am new to Hibernate and for that matter new to Object Relation Database. I have a database model that I would like to refactor so as to add the persistance layer for data access rather than doing direct access.

In this regard I had some basic modelling question.

Since I already have the legacy data with primary keys and foreign keys, I am noting doen a small use case here.

I have two tables, A and B.

Table A
attribute1 PK
attribute2 PK
attribute3 PK

Table B
attribute11 PK
attribute22 PK
attribute3 PK, FK refers attribute3 in tableA

A to B is one to many.


After going through the documentation for hibernate, I find that this design encouraged. Fortunately I have the luxury of changing the design.

Hence I came up with whatever understanding I have of ORM and Hibernate

Define Class A and B

Class A
Long A_id PK
attribute1
attribute2
attribute3

Class B
Long B_id PK
attribute1
attribute2
attribute3

Class B is associated to Class A as many to one. This takes care of the FK integrity.

However, I still need to enforce the unique constraint for the composite attribute1/2/3 in class A and B.

How can I do this. Is there a better way of modelling this.

Any advice will be highly appreciated.

TIA
Shishir

Thanks Emmanuel for the link. I think I found what I was looking for at this link

http://forum.hibernate.org/viewtopic.ph ... ght=unique


I think I will stick with the option "1" as I don't want to put business logic to check for duplication or otherwise. I guess I should let that be handled best by the database.

BTW, I have been going through the Hibernate documentation and I have to give kudos to the Hibernate team for coming up with such an extensive documentation, a hard thing to come by in open source.

Thanks
Shishir

Feel free to update http://www.hibernate.org/95.html :)