One-to-many relationship in a joined-subclass?

Jonboy · **Joined:** Wed Feb 11, 2004 1:02 pm **Posts:** 2

This seems to be a basic question to me, but I read the reference documentation several times, the FAQs, and searched past topics. I've learned a lot, but I still haven't found what I'm looking for.

I have a base class A with a joined-subclass B. Class B has a one-to-many relationship with class C. The primary key in Class B (generated by class A and inherited by class B) is of course a foreign key in class C.

I am using a bi-directional relationship for the one-to-many Set, with cascade="all" and inverse="true".

When I attempt to insert data into all three tables in one transaction I get ORA-01400: cannot insert NULL into.... Hibernate generates three insert statement as expected and executes them in the correct order, but when the foreign key in class C is null. I expected this key to be what was ultimately generated and the primary key in class A. I do have the mapping for class C in a separate file than class A and B.

I would assume that a one-to-many relationship in a joined-subclass is supported and used by others.

Is there a "trick" for this type of relationship (yes, I've read the tips and tricks page as well) or some common mistakes that I can look for ? To me it seems pretty straight forward so I'm assuming that I'm just missing some small piece here.

emmanuel · **Posted:** Wed Feb 11, 2004 1:56 pm

You probably forgot to do

Code:

b.getCs().add(c);
c.setB(b); //this line

Have a look at http://www.hibernate.org/Documentation/InsideExplanationOfInverseTrue

Jonboy · **Joined:** Wed Feb 11, 2004 1:02 pm **Posts:** 2

That was the exact problem. I knew it was something small. Thanks for the link. I went back and looked at some of the other docs that I've read and it does show that in the examples; not sure how I missed that.