Hi Lukas,
as far as I recall castor docs at the moment, they say that castor only
supports bidirectional relations. While I know that some sorts of
unidirectional ralations work they are not documented.
There is an very old issue to add support for unidirectional relations which
currently is assigned to me. I intendet to write some test cases to find out
under which conditions unidirectioanl relations work and at which they do not.
To my knowledge insert statements are only part of the problem. I think main
part need to be done at Class- and FieldMolder. One thing you could try is to
allow null for the foreign key column as it may be possible that castor will
update the record inserted with the correct parent_id.
Ahmad only reorganizes current codebase around generation of SQL statements.
His focus is to keep current functionallity but after his refactoring it should
be much easier to add new features.
We can discuss this issue in more details once I'm back from holiday begin of
next week.
Regards
Ralf
Hey everybody,
I'm facing a problem when trying to map a one to many relation.
Imagine the following: A Parent entity references a List of Child
entities. The mapping is defined as follows:
<mapping>
<class name="org.castor.cpa.test.lazycollection.Child" identity="id">
<map-to table="lazy_collection_child" />
<field name="id" type="integer">
<sql name="id" type="integer" />
</field>
</class>
<class name="org.castor.cpa.test.lazycollection.Parent" identity="id">
<map-to table="lazy_collection_parent" />
<field name="id" type="integer">
<sql name="id" type="integer" />
</field>
<field name="children"
type="org.castor.cpa.test.lazycollection.Child"
lazy="false" collection="arraylist">
<sql many-key="parent_id" />
</field>
</class>
</mapping>
when executing the following statements:
Parent parent = new Parent();
parent.setId(1);
Child child1 = new Child();
child1.setId(1);
Child child2 = new Child();
child2.setId(2);
parent.setChildren(Arrays.asList(child1, child2));
// Persist entities.
_db.setAutoStore(true);
_db.begin();
_db.create(parent);
_db.commit();
_db.setAutoStore(false);
The create operation fails because the insert statement is as follows:
INSERT INTO lazy_collection_child (id) VALUES (1);
Hence, Castor results in:
java.sql.SQLIntegrityConstraintViolationException: Column 'PARENT_ID'
cannot accept a NULL value.: Column 'PARENT_ID' cannot accept a NULL
value. at
org.castor.cpa.persistence.sql.keygen.NoKeyGenerator.executeStatement(NoKeyGener
ator.java:212)
My general questions are:
Why would it not be possible to map a one to many relation only by
specifying a key column?
The Castor JDO docu does not take care of this issue. It only shows
bidirectional one to many. Has noone ever requested that feature?
Ralf, Ahmad: Any ideas, since you are rewriting SQL stmt generation?
Regards,
Lukas
PS: I'm facing this behavior with 1.2, 1.3 and 1.3.0.1-SNAPSHOT.
---------------------------------------------------------------------
To unsubscribe from this list, please visit:
http://xircles.codehaus.org/manage_email
---------------------------------------------------------------------
To unsubscribe from this list, please visit:
http://xircles.codehaus.org/manage_email
