title: How to relate entities without navigation property mappings
body: <p>I Have Database that contains 4 tables</p>
  
  <pre><code> TABLE TBLCARTITEM (CART_ID, ITEM_ID, PROMOTION_ID, many more cart item fields)
   TABLE XREFCARTITEMPROMOTION (CART_ID, ITEM_ID, PROMOTION_ID)
   TABLE TBLPROMOTION (PROMOTION_ID, PROMOTION_TYPE_ID, many more promotion fields)
   TABLE LKPROMOTIONTYPE (PROMOTION_TYPE_ID, PROMOTION_TYPE_DESCRIPTION)
  </code></pre>
  
  <p>The XREFCARTIEMPROMOTION table is a cross reference table that creates a many-to-many relationship between TBLCARTITEM and TBLPROMOTION.</p>
  
  <p>TBLPROMOTION is linked to LKPROMOTIONTYPE by PROMOTION TYPE ID.</p>
  
  <p>I am trying to use LINQ to get all of a particular carts items and related promotions.  </p>
  
  <p>So far i have everything with the exception of the LKPROMOTIONTYPE table.</p>
  
  <pre><code>using (WSE db = new WSE())
  { 
     var cartItems = db.XREFCARTITEM.Include("TBLPROMOTION")
             .FirstOrDefault(x =&gt; x.CART_ID == cartId);
  }
  </code></pre>
  
  <p>This gives me everything for the cart including the promotions tied to each item.  However when i go and try to include the LKPROMOTIONTYPE table i get the following run-time error: </p>
  
  <pre><code>A specified Include path is not valid. The EntityType 'Model.XREFCARTITEM' does not declare a navigation property with the name 'LKPROMOTIONTYPE'.
  </code></pre>
  
  <p>My question is:
  Does anyone know of a way to relate LKPROMOTIONTYPE to this cartItems object above?</p>
  
  <p>Thanks.</p>