I think you are misunderstanding the purpose. Post type is a string "question", "answer", "comment", etc, to distinguish, what of kind is the post. Why should it be a foreign key? It could have been a small int to save bytes, but it is what it is now.
It was one thing that stood out when I was looking at the admin interface. I was thinking one helpful feature request would be, e.g, to turn an answer into a comment. But you wouldn't do that through the admin interface anyways.
Comments
I think you are misunderstanding the purpose. Post type is a string "question", "answer", "comment", etc, to distinguish, what of kind is the post. Why should it be a foreign key? It could have been a small int to save bytes, but it is what it is now.
It was one thing that stood out when I was looking at the admin interface. I was thinking one helpful feature request would be, e.g, to turn an answer into a comment. But you wouldn't do that through the admin interface anyways.
We have a feature like that in the repository version.