title: Entity Framework 6.x Must specify mapping for all key properties
body: <p>I am beginning playing with EF 6.x and I've got an annoying issue.</p>
  
  <p>I've designed a database with simple User,Role,Permissions tables each one bond to another with classic many-to-many relation.</p>
  
  <p>EF wants me to create primary keys in indirect tables (UserPermissions etc.)
  but also wants me to make some mapping for those Primary Keys but I have no clue why.</p>
  
  <p>Is there something wrong with my design or there Is a workaround to this issue?
  Maybe Can I in some way use Unique index instead of Primary Key to satisfy EF?</p>
  
  <p>There you have <a href="https://i.stack.imgur.com/jjSWB.png" rel="nofollow noreferrer">diagram</a> to make it more clear:</p>
  
  <p><a href="https://i.stack.imgur.com/jjSWB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jjSWB.png" alt="enter image description here"></a></p>