Updating values - Core Data

Procedure

1. Create context object

 AppDelegate *app=[[UIApplication sharedApplication]delegate];

    NSManagedObjectContext *Obj=[app managedObjectContext];

2. Create Fetch request 

 NSFetchRequest * request = [[NSFetchRequest alloc] init];

    [request setEntity:[NSEntityDescription entityForName:@"Stations" inManagedObjectContext:Obj]];

    [request setPredicate:[NSPredicate predicateWithFormat:@"name ==%@",@"Sample string"]];

    

    

3. Execute request  and save the result in managed object (aBook is managed object class)

   

    aBook = [[Obj executeFetchRequest:request error:&error2] lastObject];

4. Check for error

 if (error2) {

        //Handle any errors

    }

    

    if (!aBook) {

        //Nothing there to update

    }

    

5. Update value and saving 

   

    aBook.name = @"BarBar";

    

    //Save it

    error2 = nil;

    if (![Obj save:&error2]) {

        //Handle any error with the saving of the context

    }