getting related data in ios swift coredata

Question

I am saving 2 tables information using core data one is Customer and other is Booked Tickets. one customer can book many tickets. I want to fetch this related data and populate in table view .I am getting all ticket data but I want ticket information of particular user. for example users.ticket.passangerName. But I am getting nil here.

import UIKit
import CoreData

class BookHistoryVC: UIViewController {

    @IBOutlet weak var tableView: UITableView!

var tickets: [BookedTickets]? {
    didSet{
        tableView.reloadData()
    }
}
var users: [Customer] = []

override func viewDidLoad() {
    super.viewDidLoad()

    tableView.delegate = self
    tableView.dataSource = self
    // Do any additional setup after loading the view.

    self.fetch { (complete) in
        if complete {
            guard  let tickets = tickets else {
                return
            }
            if (tickets.count) >= 1 {
                //tableView.isHidden = false
                print(tickets as Any)
            } else {
                return
            }

        } else {
            //tableView.isHidden = true
        }
    }//Fetch Complete

}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)


}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func fetch(completion: (_ complete : Bool) -> ()) {
    guard let managedContext = appDelegate?.persistentContainer.viewContext else { return }

    let fetchRequest1 = NSFetchRequest<NSFetchRequestResult>(entityName: "Customer")
    let fetchRequest2 = NSFetchRequest<NSFetchRequestResult>(entityName: "BookedTickets")

    do {
        users = try managedContext.fetch(fetchRequest1) as! [Customer]

        tickets = try ((managedContext.fetch(fetchRequest2) as? [BookedTickets]))
        print("Succesfully Fetched")
        tableView.reloadData()
        completion(true)
    } catch  {
        debugPrint("Could Not Fetch:\(error.localizedDescription)")
        completion(false)
    }




   }

}

extension BookHistoryVC: UITableViewDelegate, UITableViewDataSource{
    func numberOfSections(in tableView: UITableView) -> Int {
            return 1
        }

        func tableView(_ tableView: UITableView, numberOfRowsInSection 

section: Int) -> Int {
        guard  let tickets = tickets else {
            return 0
        }
        return tickets.count
    }

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    guard let cell = tableView.dequeueReusableCell(withIdentifier: "BookHistoryVCCell", for: indexPath) as? BookHistoryVCCell else { return UITableViewCell()}

    guard  let tickets = tickets else {
        return UITableViewCell()
    }

    let ticket = tickets[indexPath.row]
    cell.configureCell(ticket: ticket)

    return cell
}



 func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 400
    }


}

In cell ...

import UIKit

class BookHistoryVCCell: UITableViewCell {

    @IBOutlet weak var bookerNameLabel: UILabel!
    @IBOutlet weak var ageLabel: UILabel!
    @IBOutlet weak var passangerNameLabel: UILabel!
@IBOutlet weak var ticketNumberLabel: UILabel!
@IBOutlet weak var fromLabel: UILabel!
@IBOutlet weak var toLabel: UILabel!
@IBOutlet weak var createdLabel: UILabel!

var jsonNamesArr: [Any] = []
var jsonAgesArr: [Any] = []
var details = ""

func configureCell(ticket: BookedTickets) {

    let fullNames: String  = ticket.passangerName!
    let dataNameArray = fullNames.data(using: .utf8)
    let fullAges: String = ticket.age!
    let dataAgeArray = fullAges.data(using: .utf8)

    do {
        if let jsonNameArray = try JSONSerialization.jsonObject(with: dataNameArray!, options: .allowFragments) as? [Any] {
                jsonNamesArr = jsonNameArray
                print(jsonNameArray)
            }
        } catch {
            //            #error()
            print("Error")
        }

        do {
            if let jsonAgeArray = try JSONSerialization.jsonObject(with: dataAgeArray!, options: .allowFragments) as? [Any] {
                jsonAgesArr = jsonAgeArray
                print(jsonAgeArray)
            }
        } catch {
            print("Error")
        }

        for (name, age) in zip(jsonNamesArr, jsonAgesArr) {
            details = details + ("\(name) of \(age)\n")
            print("\(name): \(age)")
        }

        self.bookerNameLabel.text! = Utilities.getUserName()
        //self.ageLabel.text! = "Ages: \(ticket.age!)"
        self.passangerNameLabel.text! = "Passangers Details:\n\(details)" 
        self.fromLabel.text! = "From: \(ticket.fromDestination!)"
        self.toLabel.text! = "To: \(ticket.toDestination!)"
        self.createdLabel.text! = "Booked Date: \(ticket.created_at!)"
    self.ticketNumberLabel.text! = "Ticket Number: \(ticket.uniqueTicketNumber!)"
}

}

My tables images..

Answer 1

I am getting customer nil because I am not adding ticket object inside customer object.For that I have created Singleton Class and created Customer property.

import Foundation

class Singleton {

   static var user: Customer!

}

and assign customer object to singleton property in login page.

//Singleton 
                        Singleton.user = user

Now singleton object carrying current user object. while saving ticket details add this line Singleton.user.addToTickets(ticket) You can refer this link https://github.com/learnasucan/BookTicket.git

Answer 2

You need a predicate for filtering, for example you are looking for all tickets whose name of the customer is John Doe

let fetchRequest2 = NSFetchRequest<NSFetchRequestResult>(entityName: "BookedTickets")
let name = "John Doe"
fetchRequest2.predicate = NSPredicate(format: "customer.name = %@", name)

And there is no need to use a completion block in fetch. The Core Data method fetch(_ request: NSFetchRequest) works synchronously.