title: Foreign keys not working in link table in Linq2Sql
body: <p>I have 3 tables Subcontract, Company, and a link table CompanyToSubcontract.  The link table contains the Subcontract_id and the Company_id.  The foreign keys were set-up in SQL and when I drug them into my dbml the one-to-many relationship arrows showed up and everything looked fine.  However, when coding, it's as if the relationship isn't there.</p>
  
  <p>When I write a Select statement I have to use the join for it to work.  When I refer to CompanyToSubcontract in code, I don't have the correct members available. I have CompanyToSubcontract.company_id and CompanyToSubcontract.subcontract_id, but not CompanyToSubcontract.company or CompanyToSubcontract.subcontract.</p>
  
  <p>I have another table Group which has a one-to-many relationship with Subcontracts.  I set up the foreign key the same way and that's working great.  I can access Subcontract.group_id as well as Subcontract.group.</p>
  
  <p>Everything seems to be set up properly for the link table, but I cannot get it to work.  Is there some kind of trick for multiple foreign keys?  What am I missing?</p>
  
  <p>EDIT: My CompanyToSubcontract doesn't have a primary key.  Could that be causing the problem?  Trying it right now.</p>