Hello,

I have a problem with an abstact class with 2 derived classes. NHibernate tries to instanciate my abstract class, even if there are records in the joined tables corresponding to the subclasses.

If I remove the abstract, the mapping works and only objects correponding to derived classes are returned.

The mapping file looks like this :

...
<class name="ch.VibroMeter.Xms.Configuration.Xmc.XmcChannel" table="XmcChannels">
<composite-id>
<key-property name="Id" column="Id" type="Int64" />
<key-property name="Revision" column="Revision" type="Int64"/>
</composite-id>
...

<joined-subclass name="ch.VibroMeter.Xms.Configuration.Xmc.XmcSingleDynamicProcessingChannel"
table="XmcSingleDynamicProcessingChannels" lazy="false">

<key>
<column name="Id" />
<column name="Revision"/>
</key>
</joined-subclass>

<joined-subclass name="ch.VibroMeter.Xms.Configuration.Xmc.XmcSpeedProcessingChannel"
table="XmcSpeedProcessingChannels" lazy="false">

<key>
<column name="Id" />
<column name="Revision"/>
</key>

</joined-subclass>
</class>
...

The query comes from another class with a many-to-many association to the abstract class :

<set name="XmcChannelsNH" table="XmcChannelsMachinesRelations">
<key>
<column name="MachineId" />
<column name="MachineRevision" />
</key>
<many-to-many class="ch.VibroMeter.Xms.Configuration.Xmc.XmcChannel" lazy="false">
<column name="XmcChannelId" />
<column name="XmcChannelRevision" />
</many-to-many>
</set>

Thanks in advance...

This may be a lazy loading issue.

Your base class is mapped as lazy and the collection is mapped to the base class so Nhibernate might be trying to create a proxy for the abstract base class before resolving it to the subclasses when actually hydrating the proxies.

Not sure if that's the answer, but it's an avenue for investigation.

Cheers,

Symon.

Symon,

Thank you for your reply. I tried to add 'lazy="false"' to the base class, but it didn't help.

I forgot to mention that eventually, I've added the attibute 'default-lazy="false"' in the hibernate-mapping.

Cheers
Phil

Hi phgomez,

How did you solve this in the end?

Regards,

Stewart