Question

I have a data model setup with three entities, Course, Student, TestScores.

They are linked in too-many relationships like this:

Course <---->> Student <---->> TestScores

So a Course would have several Students, who in turn could have several TestScores (or no test scores)

The Course entity has a Name attribute. TestScores is a simple entity which just contains a testScore int attribute.

I want to be able to get an array of Students who have at least one textScore of 100, ordered by Course name. Is this possible with NSPredicate?

Answer 1

I think you could have your predicate as

ANY testScores.score == 100

Then put it all together in a fetch request:

NSFetchRequest *req = [NSFetchRequest fetchRequestForEntityNamed:@"Student"];
req.predicate = [NSPredicate predicateWithFormat:@"ANY testScores.score == 100"];
req.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"course.name" ascending:YES]];