If I have a Customer entity and then a specialization of Friend which inherits from Customer, how can I do a retrieve of Customers that are not Friends? Currently if I do a Retrieve action on Customer the resulting list contains Friends, and I have to loop through my list with an object type decision in that loop. Is there a better way?
Retrieve all Customer and retrieve all Friend then do a list operation substract where you substract all Friend from all Customer. The result is all Customer that are not Friend.