Question

I just cant seem to figure out how to update core data object after I fetch the object that I want to modify.

This is what I’m trying to do :

1) Find 1st object from core data matching predicate conditions :

NSInteger storeId = 235;  //find object with this id in core data

NSManagedObjectContext *context = [[NSManagedObjectContext alloc] init];
[context setPersistentStoreCoordinator:[self.managedObjectContext persistentStoreCoordinator]];

NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Store"
                                          inManagedObjectContext:context];
[request setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"id == %i",storeId];
[request setPredicate:predicate];

NSArray *results = [context executeFetchRequest:request error:NULL];

2) If match found, update matching object (This is where I need help) :

if (results != nil && [results count] > 0)
{
    /** Not sure how to get the correct context and modify object **/

    Store *matchingObject = [results objectAtIndex:0];
    [context setValue:[NSNumber numberWithInteger:storeId] forKey:"id"];
}


/** Save the context */
NSError *error = nil;
if (![context save:&error]) {     
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        //abort();
}

Thank you for any help you can provide…

Answer 1

Try modifying the object property directly and saving it:

matchingObject.id = [NSNumber numberWithInteger:storeId];

The object was originally fetched with context so you should be able to save your changes by calling save on context.