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I am having trouble mapping ports to an associated device in order to allow the cascade on delete to work. The basic object hierarchy is:

NetworkElement ------------- 1..* - PhysicalPort
|
DeviceA, DeviceB, DeviceC (derived from NetworkElement)

I'm using the table for class hierarchy approach, and I want to use a many-to-one relationship between the PhysicalPorts and their associated NetworkElement (or derived class). I don't want the NetworkElement class to contain a member variable list of PhysicalPorts - they are simply associated via the deviceId member variable in the PhysicalPort object.

If I attempt to add PhysicalPort objects that are associated with subclasses of NetworkElement (in this case a PBG), I get the "Instance not of expected entity type".

I've poured over the hibernate docs, examples, etc, but none of them use an association via derivation where a set isn't used within the NetworkElement type class. I've also tried using entity-name instead of the class name without positive results.

I'm assuming that there is some way to tell Hibernate "this and all subclasses", but I can't find the symantic in any of the docs or examples dealing with relationships.

I could just change the many-to-one relationship to a property and manually remove the PhysicalPorts via a HQL delete where clause, but that's not as efficient as having the DB do it automatically.

Any help and/or pointers will be greatly appreciated.

Hibernate version: 3.1
Name and version of the database you are using: PostgreSQL 8.0.3 on Windows XP.

Mapping documents:
<hibernate-mapping>
<class name="org.mg.core.data.PhysicalPort" table="PhysicalPort">

<id name="id" column="id">
<generator class="native"/>
</id>
<timestamp name="timestamp" column="modified"
unsaved-value="undefined" source="vm" generated="never"/>

<many-to-one name="deviceId" class="org.mg.core.data.NetworkElement"
column="deviceId" update="false" not-null="true"
unique="false" cascade="delete"
foreign-key="FK1_PORT_DEVICE_ID"/>

<!-- Other properties omitted since not relevant -->
</class>
</hibernate-mapping>

<hibernate-mapping>
<class name="org.mg.core.data.NetworkElement" table="NetworkElement"
discriminator-value="Manogia.NetworkElement">
<id name="id" column="deviceId">
<generator class="native"/>
</id>
<discriminator column="deviceType" type="string" length="255"/>

<timestamp name="timestamp" column="modified"
unsaved-value="undefined" source="vm" generated="never"/>
<property name="addedTimeStamp" type="long" column="added"/>
<!-- Other properties omitted since not relevant -->
</class>
</hibernate-mapping>

The subclasses all look like:
<subclass name="com.pannaway.pbg.core.data.PBG"
extends="org.mg.core.data.NetworkElement"
discriminator-value="Pannaway.PBG"/>


Full stack trace of any exception that occurs:
2006-04-11 11:04:59,641 80999 ERROR [org.mg.ds.server.adapters.jdbc.PhysicalPortAdapter] (NEExplorerPool_0:) PhysicalPort Add Failed:
org.hibernate.HibernateException: instance not of expected entity type: org.mg.core.data.NetworkElement
at org.hibernate.persister.entity.AbstractEntityPersister.getSubclassEntityPersister(AbstractEntityPersister.java:3298)
at org.hibernate.impl.SessionImpl.getEntityPersister(SessionImpl.java:1249)
at org.hibernate.engine.ForeignKeys.isTransient(ForeignKeys.java:180)
at org.hibernate.engine.ForeignKeys$Nullifier.isNullifiable(ForeignKeys.java:137)
at org.hibernate.engine.ForeignKeys$Nullifier.nullifyTransientReferences(ForeignKeys.java:69)
at org.hibernate.engine.ForeignKeys$Nullifier.nullifyTransientReferences(ForeignKeys.java:47)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:263)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:167)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:114)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:186)
at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:175)
at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:524)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:514)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:510)
at org.mg.ds.server.adapters.jdbc.PhysicalPortAdapter.add(PhysicalPortAdapter.java:57)

Hi, I'm having the same issue with many-to-one and subclasses. Though I'm simply trying to save a new set of objects.

Unfortunately I have found some "issues" in the Hibernate core issue tracking system that seem to relate to our scenario.

See this one (which the description most closely matches my scenario, and I believe yours too, but is a duplicate of another issue)
http://opensource.atlassian.com/project ... se/HHH-667

The root "issue" is still open, and has an expected fixed version of 3.2.2... whenever that would be.
http://opensource.atlassian.com/project ... se/HHH-422

There's several comments on the various issues that have me somewhat confused as to the state of the issue, and if there are any work-arounds.

This seems like a major issue. I have no work-around at this point, but would be very interested to know if you've come up with anything.

Also, does anyone on the Hibernate team, or anyone else who's had this issue know of a fix or work-around?

Thanks,
Thunder

My resolution was to drop Hibernate altogether and use SQL. Essentially, I have an object / relational map similar to that of hibernate, but it allows me to specify the relationship like so:

<primary-key name="physicalport_pk">
<key column="id"/>
</primary-key>
<foreign-key name="physicalport_deviceid_fk" tableref="NetworkElement"
match="simple" onupdate="no action" ondelete="cascade">
<key column="deviceId" columnref="id"/>
</foreign-key>

I wrote a simple java class to parse the constraint relationships & create the SQL from them. Now, I use the same reflection hibernate uses to update data objects (via standard java reflection), and a single set of base methods to handle all insert / update / select calls.

I found hibernate to be useful for simple cases, but it couldn't handle the more complex relationships easily. So, I replaced it with my own solution. What's funny is that it took me less time to roll the generic SQL methods & ORM xml file than to try to figure out why I couldn't get Hibernate to work. :-)