Composite DB keys with Entity Framework 4.0

Question

The re-design for a large database at our company makes extensive use of composite primary keys on the database.

Forgetting performance impacts, will this cause any

Answer 1

No, EF4 supports composite keys just fine.

The problem is a table with a surrogate key and composite keys. You can only set a single key on each model; that key can have multiple fields, but you can only have one from the designer standpoint. Not sure about manually editing xml or code only mapping.

You can set a field as an Identity and not a key if you need a composite and surrogate key on the same table. The Identity ( Id ) field won't be used by the ObjectContext or ObjectStateTracker but will increment and be queryable just fine though.