Update all value in one attribute Core Data

Question

I know how to fetch all value from one attribute in Core Data using an array. I just need to press a button and -1 all the value and save it back to the Core Data.

How can I update all the value once in swift?

Thanks.

Answer 1

Try following example it might be helpful.Replace you entity name.

  var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)

  var context: NSManagedObjectContext = appDel.managedObjectContext!
  var request = NSFetchRequest(entityName: "Params")
  var params = NSEntityDescription.insertNewObjectForEntityForName("Params", inManagedObjectContext: context) as! NSManagedObject

  if let fetchResults = appDel.managedObjectContext!.executeFetchRequest(fetchRequest, error: nil) as? [NSManagedObject] {

       if fetchResults.count != 0{
             for (var v = 0 ; v < fetchResults.count ; v++) {
              var managedObject = fetchResults[v]

             println(fetchResults)
             managedObject.setValue("-1", forKey: "value")
             context.save(nil)

                }
        }
  }