EF4 - пользовательский ObjectContext и вопрос о наследовании

If you create an ObjectSet for a base type (i.e. Post) you can't create one for derived types too, because you can retrieve instances of all types in the inheritance hierarchy from that one ObjectSet.

i.e. ctx.Posts.OfType() would return BlogEntry(s).

So the answer is to simply remove the other two sets.

If yo need to do an add for example you can do this:

ctx.Posts.AddObject(new BlogEntry {....});

no problem at all.

To help you write queries more easily you could probably add a couple of properties to your ObjectContext that look like this:

public ObjectQuery<BlogEntity> Blogs{
   get{
       return ctx.Posts.OfType<BlogEntry>() as ObjectQuery<BlogEntry>;
   }
} 

and the same for comments.

Hope this helps

Alex