Show only the objects that are not associated

Hello, In my App I have 3 entities. These are: Users, Function and Commissions. New Users don't have a Commission and also no Function. When I add Users to a Commission, I assign a Function to these Users. I use a reference selector to select the users. I want to put a contraint on this reference selector like: You can only select the Users that are not already assigned to a Commission and a Function. Can somebody help me with creating this constraint for this reference selector?
1 answers

Hi Atze,

You can achieve this by using the not expression in your XPATH:


Keep in mind that "not" is a costly operation. You should preferably prevent having to use it.