Save CoreData result array even after it is deleted from the CoreData

Question

I want to save the records in an array and delete them from the CoreData. I have tried using NSCopying but it seems that copyWithZone doesn't work on NSManagedObject. I am really stuck, any help will be appreciated.

Answer 1

Copy all the field values of your NSManagedObject to an Dictionary, and store these dictionaries in the array.

I've put together a small routine that you can implement in a NSMutableObject category that could be used to obtain that.

(please, be aware that I'm not on a Mac computer right now and there might be typos on the code, but other than that, it should work fine).

-(NSDictionary*)retrieveAsDict {
  NSMutableDictionary *aux = [[NSMutableDictionary alloc] init];
  NSDictionary *attributes = [self attributesByName];
  NSArray *attributeNames = [attributes allKeys];

  for (NSString *key in attributeNames) {
    [aux setValue:[self valueForKey:key] forKey:key];
  }

  NSDictionary *ret = [NSDictionary dictionaryWithDictionary:aux];

  // Uncomment this if not using ARC
  //[aux release];

  return(ret);
}

If you need further clarification, be sure to comment and I'll answer shortly.