Core Data in Objective-C, 3rd Edition

Bulk Deletes

The API for handling bulk deletes was added to Core Data after bulk updates. Therefore, the API is very similar.

Batch/PPRecipes/PPRDataController.m

- (void)deleteOldRecipes
{
  NSManagedObjectContext *moc = [self writerContext];
  [moc performBlock:^{
    NSDate *yearOld = [self dateFrom1YearAgo];
    NSBatchDeleteRequest *request = nil;
    NSFetchRequest *fetch = nil;
    NSBatchDeleteResult *result = nil;
    NSPredicate *predicate = nil;
    NSError *error = nil;

    fetch = [NSFetchRequest fetchRequestWithEntityName:@"Recipe"];
    predicate = [NSPredicate predicateWithFormat:@"lastUsed <= %@", yearOld];
    [fetch setPredicate:predicate];
    request = [[NSBatchDeleteRequest alloc] initWithFetchRequest:fetch];