How to update attribute with core data - swift

Question

I'm trying to write and read with core data in SWIFT. When it comes to writing new data and reading existing data everything is ok. But now I want to update a record (lets say where "pagina" is "1") and suddenly I feel completely lost! I've looked into batch update, since it seems that's the best way to do it. Unfortunately none of the tutorials I've found seem to be basic enough for me.
I've created the entity "Stories" and added three attributes: "pagina" (String), "plaats" (String) and "naam" (String). The way I was going to do this was by retrieving the Page number from txtPagina.text and storing it in the variable Pagina.
Then updating the records with the UITextField contents of txtPlaats.text and txtNaam.text where pagina = Pagina. It seems simple enough. Unfortunately I can't seem figure out batch updating.
Can anyone help me? I'm totally lost here.
#IBAction func btnSave(){
var Pagina = txtPagina.text
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
//check if data exists
var request = NSFetchRequest(entityName: "Stories")
var results:NSArray = context.executeFetchRequest(request, error:nil)!
if(results.count > 0) {
Pagina = "\(results.count)"
txtPagina.text = Pagina
//code to update plaats and naam where pagina = Pagina
} else {
var newStory = NSEntityDescription.insertNewObjectForEntityForName("Stories", inManagedObjectContext: context) as NSManagedObject
newStory.setValue(Pagina, forKey: "pagina")
newStory.setValue("\(txtPlaats.text)", forKey: "plaats")
newStory.setValue("\(txtNaam.text)", forKey: "naam")
context.save(nil)
println(newStory)
println("Object Saved.")
}
}

Answer 1

If the only problem you're having is updating a record, it looks as though your problem is that you aren't making a call to context.save() after updating it. This should solve that problem.

Answer 2

I've got something working right now, but I'm not sure it's the most efficient way:
I've created a class called Stories:
import UIKit
import CoreData
#objc(Stories)
class Stories: NSManagedObject {
#NSManaged var pagina:String
#NSManaged var plaats:String
#NSManaged var naam:String
}
Now my btnSave action is this:
#IBAction func brnSave(sender: AnyObject) {
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
var request = NSFetchRequest(entityName: "Stories")
var results:NSArray = context.executeFetchRequest(request, error: nil) as [Stories]
if (results.count > 0) {
println(results.count)
if (results.count >= txtPagina.text.toInt()) {
for res in results{
var data = res as Stories
println(data.plaats)
if (data.pagina == txtPagina.text) {
data.plaats = txtPlaats.text
data.naam = txtNaam.text
context.save(nil)
println("Page \(data.pagina) updated")
}
}
} else {
// Save new Story
var ent = NSEntityDescription.entityForName("Stories", inManagedObjectContext: context)
var newStory = Stories(entity: ent!, insertIntoManagedObjectContext: context)
newStory.pagina = txtPagina.text
newStory.plaats = txtPlaats.text
newStory.naam = txtNaam.text
context.save(nil)
println("New story saved")
// Save new Story end
}
} else {
// Save new Story
var ent = NSEntityDescription.entityForName("Stories", inManagedObjectContext: context)
var newStory = Stories(entity: ent!, insertIntoManagedObjectContext: context)
newStory.pagina = txtPagina.text
newStory.plaats = txtPlaats.text
newStory.naam = txtNaam.text
context.save(nil)
println(newStory)
println("New story saved")
// Save new Story end
}
}
The code works, but doesn't seem perfect.
Is there a way to make this more efficient? When updating the array I'm basically rewriting the whole coredata table instead of just updating the changed data. I'm can only imagine what this does performance wise when there's a lot more data!