Data contains multiple values, but this cmr field is single

[jamarkha]

I've read the other posts in this forum about the subject exception message but please forgive me, I can't seem to either discern the answer (I've purchased the docs and read Chapter 6 over and over) nor overcome the problem.

I have a 1-to-1 unidirectional relationship (User-->Department) and I get the exception during ejbPostCreate.

My environment:

JBoss 3.2.0RC1 w/embedded Tomcat 4.1.18
Sun JDK 1.4.1-b21
PostgreSQL 7.3

---------------------
ejb-jar.xml
---------------------
<ejb-relation >
<ejb-relation-name>departments-pfinet_users</ejb-relation-name>
<ejb-relationship-role >
<ejb-relationship-role-name>pfinet_user-has-department</ejb-relationship-role-name>
One
<relationship-role-source >
<ejb-name>PfinetUser</ejb-name>
</relationship-role-source>
<cmr-field >
<cmr-field-name>department</cmr-field-name>
</cmr-field>
</ejb-relationship-role>
<ejb-relationship-role >
<ejb-relationship-role-name>department-has-pfinet_user</ejb-relationship-role-name>
One
<relationship-role-source >
<ejb-name>Department</ejb-name>
</relationship-role-source>
</ejb-relationship-role>
</ejb-relation>
---------------------
jbosscmp-jdbc.xml
---------------------
<ejb-relation>
<ejb-relation-name>departments-pfinet_users</ejb-relation-name>
<foreign-key-mapping/>
<ejb-relationship-role>
<ejb-relationship-role-name>pfinet_user-has-department</ejb-relationship-role-name>
<fk-constraint>true</fk-constraint>
<key-fields/>
<read-ahead>
on-load
</read-ahead>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>department-has-pfinet_user</ejb-relationship-role-name>
<key-fields>
<key-field>
<field-name>id</field-name>
<column-name>department</column-name>
</key-field>
</key-fields>
</ejb-relationship-role>
</ejb-relation>
---------------------
Entity EJB snippet where 'Department' is the local interface for the Department entity.
---------------------
...
public PfinetUserPK ejbCreate(PfinetUserValue data, Department department) throws CreateException
{
setUserId(data.getUserId());
setPfinetUserValue(data);

return null;
}
public void ejbPostCreate(PfinetUserValue data, Department department) throws CreateException
{
setDepartment(department);
}

[swankjesse]

I wrestled with this problem all day. The solution is to add target-multiple="yes" to the corresponding ejb.relation.

* @ejb.relation
* name="Message-ToUser"
* role-name="Message-has-ToUser"
* target-ejb="User"
* target-role-name="ToUser-belongs_to-Message"
* target-multiple="yes"

This causes the XDoclet-generated ejb-jar.xml to include Many in the appropriate ejb-relationship-role:

<ejb-relationship-role>
<ejb-relationship-role-name>Message-has-ToUser</ejb-relationship-role-name>
Many
<relationship-role-source >
<ejb-name>Message</ejb-name>
</relationship-role-source>
<cmr-field >
<cmr-field-name>to</cmr-field-name>
</cmr-field>
</ejb-relationship-role>


My guess is that JBoss assumes the relationship is 1:1, so it does the search on the wrong table when trying to decide what to insert or remove.

[swankjesse]

I wrestled with this problem all day. The solution is to add the XDoclet target-multiple="yes" attribute to the ejb.relation tag of the problematic relation:

* @ejb.relation
* name="Message-ToUser"
* role-name="Message-has-ToUser"
* target-ejb="User"
* target-role-name="ToUser-belongs_to-Message"
* target-multiple="yes"

This corresponds to the following XML in ejb-jar.xml:

<ejb-relationship-role >
<ejb-relationship-role-name>Message-has-ToUser</ejb-relationship-role-name>
Many
<relationship-role-source >
<ejb-name>Message</ejb-name>
</relationship-role-source>
<cmr-field >
<cmr-field-name>to</cmr-field-name>
</cmr-field>
</ejb-relationship-role>