Intense Core Data migration

gistfile1.m

- (BOOL) createRelationshipsForDestinationInstance:(NSManagedObject *) destinationAttendance entityMapping:(NSEntityMapping *)mapping manager:(NSMigrationManager *)manager error:(NSError **)error {
	
	NSArray *sourceAttendances = [manager sourceInstancesForEntityMappingNamed:[mapping name] 
														  destinationInstances:[NSArray arrayWithObject:destinationAttendance]];
	NSManagedObject *sourceAttendance = [sourceAttendances objectAtIndex:0];
	
	NSArray *allStudents = [[[sourceAttendance valueForKey:@"theSchedule"] valueForKey:@"theCourse"] valueForKey:@"students"];
	NSArray *presentStudents = [sourceAttendance valueForKey:@"students"];
	NSLog(@"For attendance on %@", [sourceAttendance valueForKey:@"date"]);
	
	for (NSManagedObject *a_student in allStudents) {
		NSManagedObject *destination_student = [[manager destinationInstancesForEntityMappingNamed:@"StudentToStudent" 
										   sourceInstances:[NSArray arrayWithObject:a_student]] 
												objectAtIndex:0];
		NSManagedObject *presence = [NSEntityDescription insertNewObjectForEntityForName:@"Presence" 
																  inManagedObjectContext:[manager destinationContext]];
		if ([presentStudents containsObject:a_student]) {
			[presence setValue:[NSNumber numberWithBool:YES] forKey:@"present"];
			NSLog(@"Created a present for %@ %@", [a_student valueForKey:@"firstName"], [a_student valueForKey:@"lastName"]);
		}
		else {
			[presence setValue:[NSNumber numberWithBool:NO] forKey:@"present"];
			NSLog(@"Created an absence for %@ %@", [a_student valueForKey:@"firstName"], [a_student valueForKey:@"lastName"]);
		}
		[presence setValue:destination_student forKey:@"student"];
		[presence setValue:destinationAttendance forKey:@"attendance"];
	
	}
	
	return YES;
}