In res.partner model there is a field named image. I can't see this field and also some other fields in the table in the database. Why is that?

I see that res.partner model is inherited from format.address.mixin and strangely enough there is no table named format.address.mixin in the db. What's happening? I got  to know that tables are defined with the model name so why can't i see few model named tables.... Am i missing something?