On Nov 27, 2009, at 17:14, Yi Lin wrote:
> For example, if I have a relationship called "shape" that refers to the Shape
> abstract entity, with concrete classes Triangle, Square, etc. In the mapping
> model, there's no sensible setting for the Mapping Name field of "shape". If
> I set the Mapping Name to TriangleToTriangle, then Square relationships will
> not be set. And if I set the Mapping Name to "Shape", than the relationship
> would not be set at all because there are no concrete instances of Shape.
If the relationship "shape" is defined to be to a Shape entity, it seems that
the correct mapping would be SomethingToShape. ("Something" is the entity from
which the "shape" relationship emanates, but you didn't say what entity that
was.) Even though there aren't any concrete instances of Shape, the actual
instances (Triangle, Square, etc) *are* also Shape objects.
Perhaps the confusion arises because Leopard Core Data doesn't properly create
the mappings for migrating abstract entities. (I don't know if this is fixed in
Snow Leopard, but I suspect not.) If that's the problem, then adding the
missing mapping should give you a usable mapping model.
Or have I missed your point?
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