I really love using Hibernate but sometimes I just get so stuck. I'm using a table-per-concrete class type structure and have a class that looks like this:



My Comp table is the parent.
My Subcomp table is the child.

My Category table is an occassional relationship between some Subcomp records and a Category record. It certianly doesn't happen on every record.

As you can see I have tried defining fetch="join", not-found="ignore" and cascade="none" in the hope that one of these might signify an optional join. However it doesn't work - Hibernate still forces a foreign key constraint from column _category to the _id column of the Category table.

There is nothing defined in the Category table that makes any reference to the Subcomp table, and as such this is only a unidirectional link.

I have searched through endless documentation, forums and websites but found no way of creating an optional relation.

I can only see two options open to me:

1. Is to manage the relationship in my code, that is simply define a property 'category_id' and in my Subcomp table and manually retrieve the Category record when required.

2. Is to manually drop the foreign key constraint - the application works normally following this, however it then becomes an additional step required during installation - and it is certainly not an elegant solution.

Is there a better (more elegant) solution???

Cheers
Murray