Hi all,

i have used Hibernate successfully in a couple of projects but now i am lost and need help.
a part of a ( unfortunately unchangeable ) db schema looks like this:

service
=====
tech_id ( primary_key )
service_id ( unique_constraint_1 )
service_version ( unique_constraint_1 )
...

service_details
==========
tech_id ( primary_key )
service_id ( foreign_key_1 )
service_version ( foreign_key_1 )
...

AFAIK Hibernate does support:
- composite primary keys
- a FK relationship to a (single column, non pk) unique constraint

But we want to map a composite foreign key to a (non primary key) composite unique constraint.

Would anyone - may be even someone from the hibernate team ... christian, gavin ... - please be so kind, to make a definite statement, if such a mapping is possible with hibernate (annotations) or not.

Thanks for helping

I think it is possible. In our project we have a one-to-one relation that uses multiple non-primary key columns. Given that one-to-one relations usually have more restrictions than many-to-one associations I think it is possible.

Since we are only using xml mapping files in our project, I can only give you xml examples. Hopefully you will be able to convert it to annotations.

1. In your 'service' class you have to group together the properties that makes up the unique constraint. This is done with the <properties> mapping.



2. In your 'service_details' class you have to do include the two foreign key columns in one <many-to-one> mapping:



The above should give you a uni-directional association from service_details to service. We are not mapping the inverse direction in our project, so I don't how easy/hard it is.

Thanks for your response.
Unfortunately there is no property/property-ref annotation.
I played around with the @JoinColumn(s) annotation without success until now.

Any other idea welcome. Thanks in advance