Hi. My apologies if this question betrays my status as an EJB neophyte. I _think_ it's a JBoss question, not a general EJB question. Here goes:
I'm having a bit of trouble declaring a many-to-many relationship on
one of my CMP beans. Specifically, I want to create trees (i.e.,
graphs with no cycles) with the beans. I've implemented this by
declaring a collection to hold a bean's parent beans and a collection
to hold its child beans, and relating them via an M2M relation.
The trouble is, I haven't made my intent clear to JBoss -- when I
deploy the bean, it stores the collections of parent and child nodes
as serialized objects, rather than as CMP-related fields in a relation
table. (For instance, if I add a bean X to bean Y's list of children,
the container just serializes Y's collection of children into a blob,
rather than writing the relation to a relation table.)
The relevant snippet of code is:
/**
* Retrieve the Policy's ChildPolicies. Note that only AND and OR policies
actually use these.
*
* @return Returns the Policy's ChildPolicies as a Collection
*
* @ejb:persistent-field
*
* @ejb:relation name="PolicyHierarchy"
* role-name="policy-has-children"
*
* @jboss.relation related-pk-field="id" fk-column="CpolicyIdFkchild"
* @jboss.relation-mapping style="relation-table"
* @jboss.relation-table table-name="policytrees"
* @jboss:create-table create="true"
* @jboss:remove-table remove="true"
* @ejb:interface-method view-type="local"
**/
public abstract Collection getChildPolicies();
/**
* Set the Policy's ChildPolicies
*
* @param pChildPolicies The Policy's ChildPolicies
* @ejb:interface-method view-type="local"
**/
public abstract void setChildPolicies( Collection pChildPolicies );
/**
* Retrieve the Policy's ParentPolicies. Note that only AND and OR policies
actually use these.
*
* @return Returns the Policy's ParentPolicies as a Collection.
*
* @ejb:persistent-field
*
* @ejb:relation name="PolicyHierarchy"
* role-name="policy-has-parents"
* @jboss:relation related-pk-field="id" fk-column="CpolicyIdFkparent"
* @jboss.relation-mapping style="relation-table"
* @jboss.relation-table table-name="policytrees"
* @ejb:interface-method view-type="local"
**/
public abstract Collection getParentPolicies();
/**
* Set the Policy's ParentPolicies.
*
* @param pParentPolicies The Policy's ParentPolicies
* @ejb:interface-method view-type="local"
**/
public abstract void setParentPolicies( Collection pParentPolicies );
When I compile and deploy, this bean creates the following table in
the database:
mysql> describe Policy;
+----------------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------------+---------------------+------+-----+---------+-------+
| Id | varchar(255) binary | | PRI | | |
| Name | varchar(255) binary | YES | | NULL | |
| MetaPolicyName | varchar(255) binary | YES | | NULL | |
| IsTLP | tinyint(4) | YES | | NULL | |
| isReady | tinyint(4) | YES | | NULL | |
| AttributeTable | longblob | YES | | NULL | |
| childPolicies | longblob | YES | | NULL | |
| parentPolicies | longblob | YES | | NULL | |
+----------------+---------------------+------+-----+---------+-------+
Note the last two fields: the container evidently thinks I wanted to
serialize the collections to childPolicies and parentPolicies, rather
than store them as relations in the table "policytrees".[0] (It does
create `policytrees'; it just doesn't use it.)
Is there some obvious mistake I've made in the xdoclet tags?
(Following the template[1], I've used xdoclet to generate all of the
.xml files).
Many thanks in advance,
--Joe Barillari
[0] Incidentally, if I don't declare the relation-table's name
explicitly, the container generates it using the bean's name. However,
because the bean's name has a slash in it (@ejb:bean
name="test/Policy"), this makes mysql choke). I assume this is a bug
-- if `/' can't appear in identifiers, the container should issue a
warning.
[1] I've based this bean on the template by Andreas
Schaefer in JBoss.3.0TemplateAndExamples.zip.
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