I have two tables. Header has a FK to State. Header stores a "state" code. As I fetch Header objects I want a "State" object associated with each Header. I created a "State" property in class Header (with associated getters and setters.) How do I associate these tables? I tried to use the one-to-one element in the Header mapping, but that seems to demand that State have a FK to Header's primary key. How do I associate State with Header's "state_code" property?