gistfile1.m

  fetchRequest.entity = [RNPFeedListEntry entityInManagedObjectContext:self.managedObjectContext];
  // this is the main predicate to get the feed entries that belong to the us
  NSPredicate *ownerPredicate = [NSPredicate predicateWithFormat:@"%K == %@ AND %K.%K == %@", 
        RNPFeedListEntryRelationships.owner, self, RNPFeedListEntryRelationships.feed, 
        RNPFeedAttributes.action, @(FeedAction_LIKE), self];
  // this is the predicate to check that we have the required item
  NSPredicate *itemPopulatedPredicate = [NSPredicate predicateWithFormat:@"(%K.%K != nil AND %K.%K != nil) OR (%K.%K == nil)", 
        RNPFeedListEntryRelationships.feed, RNPFeedAttributes.itemId, 
        RNPFeedListEntryRelationships.feed, RNPFeedRelationships.item, 
        RNPFeedListEntryRelationships.feed, RNPFeedAttributes.itemId];
	fetchRequest.predicate = [NSCompoundPredicate andPredicateWithSubpredicates:@[ownerPredicate, itemPopulatedPredicate]];