CMP/CMR Why do relationship keys have to be primary keys of
Hi All,
I have three tables. TableA, TableB, and a M:M link between them TableA_B. The link table has a record
for each association of a TableA and TableB record. This is a typical many-to-many relational problem.
The association table has one-to-many ralationship with both TableA and TableB.
Question 1:
----------
It seems that the keyfields in each relationship role must be primary keys of the associated entity on
that side of the relationship. In my case (and in most real life cases) the relationship table has two foreign
keys, one pointing to each associated table. So the two keys are not primary keys in the relationship table. Why
is JBoss expecting TableB_ID (see below in the key-fields entry) to be a primary key of TableA_B
It throws the following exception because TableBrecs (see error below) is not a field which is associated with a primary key
of the association table. (Of course it isn't. It should be a foreign key! What am I missing?)
20:23:50,347 INFO [EjbModule] Deploying TableA_EJB
20:23:50,728 INFO [EjbModule] Deploying TableB_EJB
20:23:50,758 INFO [EjbModule] Deploying TableA_B_EJB
20:23:51,389 ERROR [EntityContainer] Starting failed jboss.j2ee:jndiName=TableA_EJB,service=EJB
org.jboss.deployment.DeploymentException: Role 'TableA_B-has-many-TableBrecs' on Entity Bean 'TableA_B_EJB' : CMP field for
key not found: field name='TableBrecs'
at org.jboss.ejb.plugins.cmp.jdbc.metadata.JDBCRelationshipRoleMetaData.loadKeyFields(JDBCRelationshipRoleMetaD
ta.java:423)
at org.jboss.ejb.plugins.cmp.jdbc.metadata.JDBCRelationshipRoleMetaData.init(JDBCRelationshipRoleMetaData.java:
84)
at org.jboss.ejb.plugins.cmp.jdbc.metadata.JDBCRelationMetaData.(JDBCRelationMetaData.java:354)
at org.jboss.ejb.plugins.cmp.jdbc.metadata.JDBCApplicationMetaData.(JDBCApplicationMetaData.java:471)
Question 2:
-----------
Do I need to declare the cmr fields in either ejb-jar.xml or jbosscmp-jdbc.xml as cmp fields as well? Presently I
only list them in the relationships section as show below:
ejb-jar.xml
<ejb-relation>
<ejb-relation-name>TableA_B-TableB</ejb-relation-name>
<ejb-relationship-role>
<ejb-relationship-role-name>TableA_B-has-many-TableBs</ejb-relationship-role-name>
One
<relationship-role-source><ejb-name>TableA_B_EJB</ejb-name></relationship-role-source>
<cmr-field>
<cmr-field-name>TableBrecs</cmr-field-name>
<cmr-field-type>java.util.Set</cmr-field-type>
</cmr-field>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>TableB-associated-with-a-TableATableB</ejb-relationship-role-name>
Many
<relationship-role-source><ejb-name>TableB_EJB</ejb-name></relationship-role-source>
</ejb-relationship-role>
</ejb-relation>
<ejb-relation>
<ejb-relation-name>TableA_B-TableA</ejb-relation-name>
<ejb-relationship-role>
<ejb-relationship-role-name>TableA_B-has-many-TableAs</ejb-relationship-role-name>
One
<relationship-role-source><ejb-name>TableA_B_EJB</ejb-name></relationship-role-source>
<cmr-field>
<cmr-field-name>TableArecss</cmr-field-name>
<cmr-field-type>java.util.Set</cmr-field-type>
</cmr-field>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>TableA-associated-with-a-TableA_B</ejb-relationship-role-name>
Many
<relationship-role-source><ejb-name>TableA_EJB</ejb-name></relationship-role-source>
</ejb-relationship-role>
</ejb-relation>
jbosscmp-jdbc.xml
<ejb-relation>
<ejb-relation-name>TableATableB-TableB</ejb-relation-name>
<ejb-relationship-role>
<ejb-relationship-role-name>TableATableB-has-many-TableBs</ejb-relationship-role-name>
<key-fields>
<key-field>
<field-name>TableBrecs</field-name>
<column-name>TableB_ID</column-name>
</key-field>
</key-fields>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>TableB-associated-with-a-TableA_B</ejb-relationship-role-name>
<key-fields/>
</ejb-relationship-role>
</ejb-relation>
<ejb-relation>
<ejb-relation-name>TableATableB-TableA</ejb-relation-name>
<ejb-relationship-role>
<ejb-relationship-role-name>TableATableB-has-many-TableAs</ejb-relationship-role-name>
<key-fields>
<key-field>
<field-name>TableArecs</field-name>
<column-name>TableA_ID</column-name>
</key-field>
</key-fields>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>TableA-associated-with-a-TableA_B</ejb-relationship-role-name>
<key-fields/>
</ejb-relationship-role>
</ejb-relation>