I like the approach explained here: http://www.try-alf.org/blog/2013-10-21-relations-as-first-class-citizen http://www.try-alf.org/blog/2013-10-21-relations-as

I like the approach explained here: http://www.try-alf.org/blog/2013-10-21-relations-as-first-class-citizen http://www.try-alf.org/blog/2013-10-21-relations-as-first-cl... Is something like: requester_city = 'Paris' solution = suppliers # 1). A supplier may only see information about the suppliers located # in the same city than himself. solution = restrict(solution, city: requester_city) # 2) The supplier's `status` is sensitive and should not be displayed. solution = allbut(solution, [:status]) # 3). The country name must be displayed together with the supplier's city. solution = join(solution, cities) The good idea is that is composable. You can query by all the solution =