Yeah you described the cause correctly. Now forgetting about Cayenne
for a sec, is there even a way to save it with just SQL INSERTs
without violating the constraints?
Usually there isn't and the commit has to be split into INSERT ...
VALUES (NULL /* null FK */...) and an UPDATE. Cayenne can't do it
automatically, so you can either manually split it to 2 transactions,
or figure a way to configured "deferred constraint checking" on your
DB (some DB's allow that), or drop the FK constraint for this one
relationship in DB.
Andrus
On Apr 15, 2009, at 3:37 PM, Andrey Razumovsky wrote:
Hi,
I've got three entities, A, B, and C and three to-one relationships
(A->B,
B->C, C->A). When I fire code like that:
A a = context.newObject(A.class);
B b = context.newObject(B.class);
a.setToB(b);
context.commitChanges();
I *sometimes* get SQL exception at commit, saying that object in B
does not
exist when inserting A, i.e. Cayenne is insering records in wrong
order.
Seems that it just can't define order of commits because of circle
references. Can I somehow help Cayenne solve this puzzle? (I think I
can
even sacrifice some of reverse (to-many) relationships.
And what's the algorithm of sorting entities before commit?
Thanks,
Andrey
