You need to setup a fetch request like this:
NSError *aError = nil;
NSEntityDescription *entityDescription = [NSEntityDescription
entityForName:@"Employee" inManagedObjectContext:self.currentManagedObjectContext];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDescription];
NSPredicate* entriesPredicate = [NSPredicate predicateWithFormat:@"employeeName = %@", name];
NSSortDescriptor* sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];
[request setPredicate:entriesPredicate];
[request setSortDescriptors:@[sortDescriptor]];
NSArray *employeeArray = [self.currentManagedObjectContext executeFetchRequest:request error:&aError];
EmployeeObject *retrievedEmployee = [employeeArray lastObject];
NSString *retrievedPin = retrievedEmployee.employeePin;
Also, I agree with @trojanfoe you need to hash the pin before inserting it into the database.