NSFetchRequestExpression
An expression that evaluates the result of a fetch request on a managed object context.
Declaration
class NSFetchRequestExpressionOverview
NSFetchRequestExpression inherits from NSExpression, which provides most of the basic behavior. The first argument must be an expression which evaluates to an NSFetchRequest object, and the second must be an expression which evaluates to an NSManagedObjectContext object. If you simply want the count for the request, the countOnly argument should be true.