title: Combining two tables to a single entity type
body: <p>So I have this old system of two related tables, orders and orderextras. The order-table has Id as its primary key, customer name as a scalar property and an orderextra_Id as a foreign key. The orderextra has only two properties, Id as its primary key and a varchar called extrainfo.</p>
  
  <p>Now I've just began reading EF 4.0 Recipes and in quite the beginning it demonstrated combining two tables into a single entity (so basically, I'd want the extrainfo to appear on the order-entity, and not have the orderextra as an entity at all). However, in the example, both tables shared the same PK. Is it possible to do this when they have separate PKs and one of the tables references the other one?</p>