objective-c : Core Data Lightweight Migration & delete journal mode

snippet.m

//Core Data Lightweight Migration & delete journal mode


//1. add a model version
//select current xcdatamodel -> Editor > Add Model Version -> accept new version name

//2. update data model
//select new xcdatamodel -> create a new entity -> select the new entity, create an attribute you want

//3. update current model version
//select current xcdatamodel -> file inspector -> set current model version to new (Model 2) model version

//4. add following code for Lightweight Migration (migration can be handled automatically)
NSDictionary *options = @{NSMigratePersistentStoresAutomaticallyOption:@YES,
                              NSInferMappingModelAutomaticallyOption:@YES}


//sample code :

- (void)loadStore {
    
    if (debug==1) {NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));}
    
    if (_store) {
        return; // Don’t load store if it’s already loaded
    }
    
    
    //Core Data Lightweight Migration & delete journal mode
    NSDictionary *options = @{NSMigratePersistentStoresAutomaticallyOption:@YES,
                              NSInferMappingModelAutomaticallyOption:@YES,
                              NSSQLitePragmasOption: @{@"journal_mode": @"DELETE"}};
    
    NSError *error = nil;
    _store = [_coordinator addPersistentStoreWithType:NSSQLiteStoreType
                                        configuration:nil
                                                  URL:[self storeURL]
                                              options:options error:&error];
    if (!_store) {
        NSLog(@"Failed to add store. Error: %@", error);abort();
    } else {
        if (debug==1) {
            NSLog(@"Successfully added store: %@", _store);
        }
    }
}

what is NSSQLitePragmasOption: @{@"journal_mode": @"DELETE"} for ?

OK, I figured out, it's for pre iOS 7 bug fix... I don't need it then.