There is a problem with column aggregation inheritance in Doctrine 0.9. The high level summary is that it is possible to make it work in general -- if class B is a subclass of class A, you can select from class A and get back objects of class B. However, those objects do not have the related objects of class B, and in fact an exception is thrown when you try to access those related objects.

I know, it seems fruitless to sink effort into this in this branch since the whole system has been changed in later versions, but since it 'kind of' works I thought it was worth at least filing a ticket and a test case for reproducing the issue. 0.9 will be in use for some time yet so I am willing to investigate this issue.

The test case should not probably be applied to trunk and possibly not to 0.10 branch as I think the way inheritance works changed between 0.9 and 0.10.