How to delete all objects for a given entity from the ManagedObjectContext

I don't want开发者_StackOverflow社区 to use the reset method for my ManagedObjectContext. I only need to remove all of the objects for a specific entity, but I don't see any methods for doing this. Selecting all of the objects for a specific entity and looping over each and deleting them works, but it's very slow.

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Selecting all of the objects for a specific entity and looping over each and deleting them works

That's pretty much how you do it.

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Categories to the rescue! Again.

NSManagedObjectContext+MyExtensions.h

@interface NSManagedObjectContext (MyExtensions)

-(void) deleteAllInstancesOfEntity:(NSString*) entity;

@end

NSManagedObjectContext+MyExtensions.m

#import "NSManagedObjectContext+MyExtensions.h"


@implementation NSManagedObjectContext (MyExtensions)

-(void) deleteAllInstancesOfEntity:(NSString*) entity {
     NSError* error;

     for (NSManagedObject* o in
            [self executeFetchRequest:[NSFetchRequest fetchRequestWithEntityName:entity]
                                error:&error]) {
          [o.managedObjectContext deleteObject:o];
     }
}

@end

Usage

NSManagedObjectContext *myMOC = ...;
[myMOC deleteAllInstancesOfEntity:@"SmellyCheese"];

Categories are awesome.