title: Looking for an elegant way to store one-to-many relationship in coredata when order is important
body: <p>I've been trying to come up with a way to solve my problem, but every solution I can think of is messy and makes me want to retch.</p>
  
  <p>I have a one-to-many relationship, consisting of a Team object that can have many Member objects.  When I built my data model using Xcode, I was given the default NSSet in which to store the member objects, Unfortunately Sets are not ordered and I need to preserve the order of the Member objects and I need to know if there are empty spaces between Members.</p>
  
  <p>I thought of Using an NSArray in place of the NSSet and creating a dummy Member object in my data store that I could use to mark vacant a spot between to Member objects, but that solution really feels like too much of a hack to me. Since I'll always have to filter out this dummy Member from any queries. </p>
  
  <p>An NSDictionary would be perfect as I could store the Member object references and their positions as Object-Key pairs, (taking care of both order and vacancies) but apparently CoreData does not support NSDictionary.</p>
  
  <p>Has anyone had a similar need, and devised a simple solution?</p>