NSPredicate compare dates in CoreData

Question

I have a managed object with two dates: dateOne and dateTwo and I want to retrieve the dates where dateTwo is older than dateOne.

Right now I am using the following predicate to fetch the objects:

NSArray *objects = nil;

NSFetchRequest *request = [[NSFetchRequest alloc] init];
request.entity = [NSEntityDescription entityForName:@"Object" inManagedObjectContext:context];
request.predicate = [NSPredicate predicateWithFormat:@"dateOne > dateTwo", @""];

objects = [context executeFetchRequest:request error:nil];
[request release];

Sometimes it works, but other times the objects fetched have a dateTwo that is more recent than dateOne. Is there a better way to do something like this?

Thanks!

Answer 1

也许您可以向实体添加BOOL属性“ dateTwoIsOlder”，然后仅获取遵守该属性的对象？

Answer 2

为什么不只从核心数据创建fetch request ，而不能以编程方式进行呢？