title: Composite DB keys with Entity Framework 4.0
body: <p>The re-design for a large database at our company makes extensive use of composite primary keys on the database.</p>
  
  <p>Forgetting performance impacts, will this cause any difficulties when working with this db in Entity Framework 4.0? The database structure is unlikely to change and I'm not looking for "philosophical" debate but what are the practical impacts?</p>
  
  <p>According to <a href="http://codebetter.com/blogs/jeremy.miller/archive/2007/02/01/Composite-keys-are-evil.aspx" rel="noreferrer" title="Codebetter blog site">Jeremy Miller</a>, "Composite key make any kind of Object/Relational mapping and persistance in general harder." but he doesn't really say why.  Is this relavent to how Entity Framework 4.0 handles keys?</p>