Delete all records in NSManagedObjectContext

Question

Is there a way to delete all the records from an NSManagedObjectContext?

I\'m using the following code to insert data:

NSManagedObjectContex         


        

Answer 1

To delete all instances of a given entity (we'll use your ShoppingBasket), you can simply fetch all baskets then delete them. It's just a few lines of code:

NSManagedObjectContext * context = [self managedObjectContext];
NSFetchRequest * fetch = [[[NSFetchRequest alloc] init] autorelease];
[fetch setEntity:[NSEntityDescription entityForName:@"ShoppingBasket" inManagedObjectContext:context]];
NSArray * result = [context executeFetchRequest:fetch error:nil];
for (id basket in result)
    [context deleteObject:basket];

The alternative in a non-document-based app is to shut down your connection to the data store, delete the actual file, then reconnect (the template code that comes with a standard Core Data project will automatically create the file if it's absent). You then have a brand new, empty store.

Note, the code example ignores any possible error. Don't do that. :-)

Answer 2

A much quicker way would be to just remove store entirely. This way you're not wasting any time fetching objects, or enumerating through them as the other answer does.

NSError *error;
NSURL *applicationDocumentsDirectory = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
NSURL *storeURL = [applicationDocumentsDirectory URLByAppendingPathComponent:@"MyCDStore.sqlite"];
[[NSFileManager defaultManager] removeItemAtPath:storeURL.path error:&error];

Don't forget to re-create it after you have deleted it.