Hi,

I have a 1 to N association with a class Photo at the 1-side and an interface Selection at the N-side.

The Selection-interface is implemented by the two classes RectangleSelection and PolygonSelection which are the classes I want actually to be persistent. Each of these two classes has its own table in the database. Selection does not exist in the database as it is not an instantiable class.

As the selection interface is not itself a persistent class (but the classes implementing the selection interface are), I do not create a mapping file for Selection. But as there is no mapping file for the Selection interface, hibernate can't map the association Photo->Selection (net.sf.hibernate.MappingException: Association references unmapped class: de.armax.ce.savas.entity.Selection) which is quite logical but unfortunately not what I need.

Is there any kind of "virtual" mapping to tell hibernate just that there is a class/interface (that is not really mapped to a db table) so it could map my association? Or does anyone know another workaround for this problem.

Any help would be appreciated.

Peter

I think similar problem was discussed recently: http://forum.hibernate.org/viewtopic.ph ... base+class

You're right. The problem is similar (an I admit, I did not read the posts) but not the same ;-).

I read through the posts but I did not find the answer to my question. Obviously one must not integrate mappings for abstract classes or interfaces and it will work for hibernate queries.

But my problem is that hibernate fails to initialize because onother class contains a reference to the interface, that has no mapping file. See mapping for Photo below. Selection is an interface and has no mapping defined (the classes implementing Selection have defined mappings).



I get an net.sf.hibernate.MappingException: Association references unmapped class: de.armax.ce.savas.entity.Selection

So my question is: how can I make a reference to such an interface?

Thanks,

Peter

You have two choices. Either:

(1) map the interface as a <class>, and its implementors as subclasses
(2) use a <many-to-any> mapping