Cocoa Core Data efficient way to count entities

Question

I read much about Core Data.. but what is an efficient way to make a count over an Entity-Type (like SQL can do with SELECT count(1) ...). Now I just solved this task with s

Answer 1

I believe the easiest and the most efficient way to count objects is to set NSFetchRequest result type to NSCountResultType and execute it with NSManagedObjectContext countForFetchRequest:error: method.

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:entityName];
fetchRequest.resultType = NSCountResultType;
NSError *fetchError = nil;
NSUInteger itemsCount = [managedObjectContext countForFetchRequest:fetchRequest error:&fetchError];
if (itemsCount == NSNotFound) {
    NSLog(@"Fetch error: %@", fetchError);
}

// use itemsCount