SUBQUERY in NSPredicate and NSInvalidArgumentException

Question

I set up the following model in Core Data.

Book has a to-many relationship, called toBookOrders, with OrderBook entity. The inverse is called toBook.
Book ha         


        

Answer 1

Separate the isSync == 0 and SUBQUERY into separate NSPredicates, add them to an NSArray then use [NSCompoundPredicate andPredicateWithSubpredicates:array] to get them joined into a single one to pass to your NSFetchSpecification.