title: Combine two table in one Entities Framework entity with DefiningQuery
body: <p>I am having difficulties combining two entities into one where one is a DefiningQuery of readonly data. </p>
  
  <p>I have a Person entity and a Company entity the Person entity is related to the Company entity throught the Company.CompanyID to the Person.CompanyID as one-to-many.  The data for the Company comes from a different database so its represented as a DefiningQuery in my SSDL with a key.  I want to make the fields in Company part of the Person entity by combining the entities.  </p>
  
  <blockquote>
    <p>Error 3024: Problem in mapping
    fragments starting at line 445:Must
    specify mapping for all key properties
    (Person.PersonID) of the EntitySet
    Person.</p>
  </blockquote>
  
  <p>I assume the issue is that the Company entity does not have a PersonID but I don't want to make a Company a DefiningQuery with both PersonID and CompanyID</p>