title: Binding to a relations property in Core Data
body: <p>I'm new in Core Data, and i got a problem i can't get my head around how to do "the right way"</p>
  
  <p>I'll try and examplify my problem.</p>
  
  <p>I got a entity Car. And a list of all the cars in my program. The cars have some attributes, but they are not predefined. So for each car i want to be able to define some properties. 
  Therefore i have defined a new entity CarProperty, with a one to many relation with the car. </p>
  
  <p>In the nscollectionview i would like to show some of the properties from the car, more specefic the number of kilometer (numKm) it has driven (if that property exist). So i want to bind it to a label. But how to do? </p>
  
  <p>I can't say <code>representedObject.properties.numKm</code>, or <code>representedObject.numKm</code>.</p>
  
  <p>How should I get around this?</p>
  
  <p>Hope it makes sense.</p>