NSPredicate with a !=?

Question

I have Core Data Entities Person and Boundary. They have a many-to-many relationship (each person can have many boundaries, and each boundary can have many persons).

I a

Answer 1

[NSPredicate predicateWithFormat:@"ANY persons != %@", fred]

finds all objects that are related to any person other that Fred. What you want is

[NSPredicate predicateWithFormat:@"NOT(ANY persons = %@)", fred]

and this should return all objects that are not related to Fred.

However, there seems to be a Core Data bug that "NOT ANY" or "NONE" do not work correctly in a predicate, compare NSPredicate Aggregate Operations with NONE. The workaround is to use a SUBQUERY:

[NSPredicate predicateWithFormat:@"SUBQUERY(persons, $p, $p == %@).@count == 0", fred]