将Linq中的外键设置为SQL

It's well known that you cannot set foreign key IDs directly in Linq to SQL if the entities have already been loaded. You can however look up the entity by it's foreign key and then set the entity as the foreign entity using the entity relationship. (I've taken out the enum here and used integer values for simplicity). i.e. If I have a loaded Appointment entity and an associated AppoinmentStatus Entity I can't do this:-It's well known that you cannot set foreign key