Core DataのEntityのデータを全て削除する

Core DataのEntityに登録されたデータを全て削除する方法。

NSFetchRequest * requestDelete = [[[NSFetchRequest alloc] init]autorelease];
[requestDelete setEntity:[NSEntityDescription entityForName:@"DataModel" inManagedObjectContext:managedObjectContext]];
[requestDelete setIncludesPropertyValues:NO]; //only fetch the managedObjectID

NSError * error = nil;
NSArray * dataArray = [managedObjectContext executeFetchRequest:requestDelete error:&error];
//error handling goes here
for (NSManagedObject * data in dataArray) {
[managedObjectContext deleteObject:data];
}
NSError *saveError = nil;
[managedObjectContext save:&saveError];

参考記事：
http://stackoverflow.com/questions/1383598/core-data-quickest-way-to-delete-all-instances-of-an-entity