Hello,

I'm new to hibernate and am fast becoming a big fan. I have just convinced a a client to use it after a big POC shootout between toplink, JDO and Hibernate.

Now I have questions!

The project is an oracle 9i database that we have little control over. There are two tables in the db which should be one, but legacy architecture does not permit this.

The tables are connected via a 1-1 link and there is no primary key in the second table. The tables are only ever updated using a join.

I have considered using the foreign key in the second table as the primary, then using the assigned generator to populate it by pulling back the primary key from the first. Although this seems a very messy solution.

I notice in the CVS log that mutiple table mapping across one class using a join has been made possible although I can not find any documentation or discussion on this.

Any help or otehr solutions would be most gratefully appreciated.

Many Thanks for a great product,
F.

well, if you don't mind the two tables mapping to two different hibernate classes with a one-to-one association I think section 5.1.11 (primary key association) of the online HTML documentation should be able to give you what you need. It describes how to use ids of type "foreign."

Josh

I'm pretty sure that the ability to map a class across multiple tables is only targetted for hibernate3 with no plans to backport it to hibernate2. But I may be incorrect there. At any rate, it would still have the same limitations as the one-to-one mapping.

Just to understand better, you have two tables which logically represent a one-to-one relationship but semantcially implement a one-to-many relationship (the many side having an fk back to the one side's pk)? If thats the case, just use the one-to-one mapping using the property-ref attribute. Check out the docs regarding "unique foreign key associations" under http://www.hibernate.org/hib_docs/reference/en/html/mapping.html#mapping-declaration-onetoone

We *may* backport the new ClassPersister heirarchy from the current 3.0 branch to the 2.1 branch, once we are satisfied that it is stable in CVS. But no promises.

Thank you all for your speedy and helpful replies.

Steve you have my problem correct apart from there being no pk in the secondary table, so I cannot use the fk, unique="true" solution.

Am I right in thinking that if I use the foreign id generator solution on the fk in the secondary table it should work anyhow?