Core Data RelationShip Swift

I have the following example to understand the relationships between entities in Core Data , (brand model), I have car brands respectively and now I want to add models to these car brands for this I have registered in vieDidLoad some brands and When I choose a brand, I set a UIAlertViewController where it will allow me to capture a model for this brand but I do not know how to relate this model to that previously created object , assuming it was something dynamic. Next I add my code; the id of the objects I keep in an array of String and now I compare it with a Predicate but the result that returns to me comes out with quotes. In the predicate of the fix Id[indexPath.row]

with quotes in the predicate

* predicate: SELF == "0xd000000000040000<x-coredata://A94EA723-56E4-475B-8D1B-582FC4C58CCD/MARCA/p1>"

NSOBJECT without quotes

*  predicate: SELF == 0xd000000000040000<x-coredata://A94EA723-56E4-475B-8D1B-582FC4C58CCD/MARCA/p1>

//
//  ViewController.swift
//  Audi
//
//  Created by MACBOOK on 28/04/16.
//  Copyright © 2016 mossito. All rights reserved.
//

    import UIKit
    import CoreData


    let appDelegado:AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
    let contexto:NSManagedObjectContext = appDelegado.managedObjectContext

    class ViewController: UIViewController,UITableViewDelegate,UITableViewDataSource {
        @IBOutlet weak var myTable: UITableView!

        var textFeild:UITextField!

        var arreglo:[String] = [String]()
        var arreglosId:[String] = [String]()
        //var tamano:Int = 0

        override func viewDidLoad() {
            super.viewDidLoad()


            let entityMarca =  NSEntityDescription.entityForName("MARCA", inManagedObjectContext: contexto)

            let newMarca = NSManagedObject(entity: entityMarca!, insertIntoManagedObjectContext: contexto)
            newMarca.setValue("NISSAN", forKey: "nombre")


            let newMarca1 = NSManagedObject(entity: entityMarca!, insertIntoManagedObjectContext: contexto)
            newMarca1.setValue("FIAT", forKey: "nombre")
            //print(newMarca1)

            let newMarca2 = NSManagedObject(entity: entityMarca!, insertIntoManagedObjectContext: contexto)
            newMarca2.setValue("BWM", forKey: "nombre")
            //print(newMarca2)

            let newMarca3 = NSManagedObject(entity: entityMarca!, insertIntoManagedObjectContext: contexto)
            newMarca3.setValue("FORD", forKey: "nombre")
            //print(newMarca3)

            let newMarca4 = NSManagedObject(entity: entityMarca!, insertIntoManagedObjectContext: contexto)
            newMarca4.setValue("CHEVROLET", forKey: "nombre")
            //print(newMarca4)

            let newMarca5 = NSManagedObject(entity: entityMarca!, insertIntoManagedObjectContext: contexto)
            newMarca5.setValue("FERRARI", forKey: "nombre")
            //print(newMarca5)
            do{
                //Inserto(guardo) en BD
                try contexto.save()
                //print(newMarca.description)
                print("Insertando marca")
            }catch {
                print("Aqui hubo un error:-----\(error)")
            }


            arreglo.removeAll()

            let consulta = NSFetchRequest(entityName: "MARCA")
            if let resultados = try?contexto.executeFetchRequest(consulta) {

                for x in resultados {
                    arreglo.append("\(x.valueForKey("nombre")!)")
                    arreglosId.append("\(x.objectID)")
                }
            }



        }
        override func viewDidAppear(animated: Bool) {
            super.viewDidAppear(animated)


        }

        func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

            let celda = UITableViewCell(style:UITableViewCellStyle.Subtitle, reuseIdentifier: "Cell")
            celda.textLabel?.text = arreglo[indexPath.row]
            return celda
        }

        func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
            return arreglo.count
        }


        func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
            var identificador = arreglosId[indexPath.row]
            var valorTexto:String =  ""
    //        
      // let newMarca = NSEntityDescription.insertNewObjectForEntityForName("MARCA", //inManagedObjectContext: contexto)
       // newMarca.setValue("x", forKey: "nombre")
         //   _ = try? contexto.obtainPermanentIDsForObjects([newMarca]);

         let alerta = UIAlertController(title:"Agrega modelo", message: "Registra un nuevo modelo ha esta marca", preferredStyle:.Alert)
            alerta.addTextFieldWithConfigurationHandler(configuredTextField)
            let action =  UIAlertAction(title: "OK", style: .Default, handler: {
                (alerta)->Void in
                 valorTexto = self.textFeild.text!
                print(valorTexto)
                let consulta = NSFetchRequest(entityName: "MARCA")
                /**========= PROBLEMA*/
                consulta.predicate = NSPredicate(format: "SELF = %@", NSManagedObject(self.arreglosId[indexPath.row]))
                 print("consulta \(consulta)")
                if let results =  try? contexto.executeFetchRequest(consulta) where results.count > 0 {
                    for x in results {
                    print("valor de x  \n\(x)")
                    }
                }else{
                   print("No hay registros")
                }
            })
           alerta.addAction(action)
           presentViewController(alerta, animated: true, completion: nil)

        }

        /**Metodo para configurar el textField  el textField*/
        func configuredTextField(text:UITextField! ){
            text.placeholder = "Descripción"
            textFeild = text
        }
    }

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