Hibernate version: 2.1.6

---

I would like to introduce an simple problem: I have two POJOs:

public class A {
private long Code_A;
private B Test;
... gets and sets ...
}

public class B {
public long Code_B;
... gets and sets ...
}

And I want to map A using <many-to-one> of B :

<many-to-one name="Test" class="B"/>

---

Okey, then imagine the situation where the database field "Test" of the table "A" is NOT UNIQUE and CAN BE NULL. So, the A's dont really NEED an B in Test, and 10000 A's can point to the same B. In SQL we can simple use an "on delete set null" constraint.

Well. In Hibernate, if I do:
A A1 = new A();
B B1 = new B();
A1.setTest(B1);
"session".store(B1);
"session".store(A1);
"session".delete(B1);

It returns an "constraint violation error" because the A1 is using B1. But, I want to delete(B1) and set "Test" on A1 as null.

How do I do that??? How do I map that???

---> Thanx for your patience!!! :) Bernardo S. A. Silva

of course, all this is possible, you must read all about cascade and parent/child relationship.

Okey,

Can you please send me the documentation references. I will read all, I promisse.

:)

I am Bernardo S. A. Silva, from Brazil (bsas at hibernate forum) and I post the <many-to-one> question that you had answer. (sorry about my terrible english)
I already map that and read a lot of the "cascade" and the "parent/child" documentation, and I still can't solve my problem... :(
My real problem is: when I create a <many-to-one> relation, hibernate ALWAYS create a constraint on the database (doesn't matter the SGBD) at the "A" table that uses "on delete restrict".
But I need to create that relation with an "on delete set null" constraint.
I am really upset and tired, cause I expend more then 5hrs to solve that simple mapping problem and doesn't solve it.

Let me give you a simple example of my problem:

POJOs:

class A {
private long Code_A;
private B Relation;
.. gets and sets ...
}

class B {
private long Code_B;
... gets and sets ...
}

XMLs:

<hibernate-mapping>

<class name="A" table="A">
<id name="Code_A">
<generator class="native"/>
</id>
<many-to-one name="Relation" class="B"/>
</class>

<class name="B" table="B">
<id name="Code_B">
<generator class="native"/>
</id>
</class>

</hibernate-mapping>

MAIN:

...
A A1 = session.saveOrUpdateCopy(new A());
B B1 = session.saveOrUpdateCopy(new B());
A1.setRelation(B1);
A1 = session.saveOrUpdateCopy(A1);
session.delete(B1);
...

Exception:

Immediate foreign key constraint violation on delete
(FK7D70BC9726DD869) Columns = A(Relation) -> B(Code_B)

_____________________________________________________________________


Why??? What I did wrong??? Please help me!!!

Sorry 'cause I am boring you, really! I am desesperated!
Thanx a lot for you patience!

Bernardo S. A. Silva

plz, anyone can help me?

Help me plz... :)