allow null cmr fields

[weiqingh]

hi there,

in ejb2.0, since one cannot set the cmr field in ejbCreate, i am seeing errors like "column foo_id_fk in table barentity cannot be null" when creating a new ejb bar, which has a relationship to ejb foo.

the error only happens on a sybase we are using, but not on oracle. i checked sybase schema and apparently the foreign key column is marked as "null not allowed". if i change it to allow null, everything works.

my question is: is there a ejb/jboss standard way of controlling the fk column not-null property just like not-null in cmp?

also is there a way to work around the problem if the schema just disallows null value? i heard there is a delay-create option in weblogic. anything similar in jboss?

thanx a lot.

[m_korotkov]

This problems exists in jboss 3.0.4 and here is the description of this issue in the standard jboss documentation on CMP.
The current implementation of JBossCMP inserts a row into the database for a new entity between ejbCreate and ejbPostCreate. Since the
EJB specification does not allow a relationship to be modified until ejbPostCreate, a foreign key will be initially set to null. There is a similar
problem with removal. This limitation will be removed in a future release.
Was it solved in 3.0.6? I'm going to try it now.
--max.

[weiqingh]

i tried jboss-3.2.0RC5 and it didn't work.

another part of the question is that is there a way to configure db schema so that null foreign key is allowed?

[m_korotkov]

I think that the only way to work around this limitation is to set nullable f. keys. I hate doing this but I don't see any other solution.
I found another problem - my application stopped working after migration from 3.0.4 to 3.2RC4. It deployes CMP beans, but at runtime on my findBy... call it throws sql exception - relation A14_users (one table in PostgreSQL 7.3) not found...

--mk.

[huri]

In Oracle, you can use deferred NULL constraints, which checks the constraint at commit time. Don't know if other databases have something similar.

e.g. CREATE TABLE CLIENT ( ...
STATUSID NUMBER (20) CONSTRAINT CLIENT_NN_STATUSID NOT NULL INITIALLY DEFERRED, ...