title: ADO.NET Entity : getting data from 3 tables
body: <p>I have following table structure:</p>
  
  <pre><code>Table: Plant
   PlantID: Primary Key
   PlantName: String
  
  Table: Party
   PartyID: Primary Key
   PartyName: String
   PlantID: link to Plant table
  
  Table: Customer
   PartyID: Primary Key, link to Party
   CustomerCode: String 
  </code></pre>
  
  <p>I'd like to have Customer entity object with following fields:</p>
  
  <pre><code> PartyID: Primary Key
   CustomerCode: String
   PartyName: String
   PlantName: String
  </code></pre>
  
  <p>I am having trouble with PlantName field (which is brought from Plant table
  I connected Customer to Party and Party to Plant with associations
  However I can not connect Customer to Plant with association ( because it does not have one) 
  I can not add Plant table to mapping, when I do that - I am getting following error:</p>
  
  <pre><code>Error 3024: Problem in Mapping Fragment starting at line 352: Must specify mapping for all key properties (CustomerSet.PartyID) of the EntitySet CustomerSet
  </code></pre>
  
  <p>Removing Plant association works.
  Any hints or directions very appreciated.</p>