How to create and save a one to many relationship (Parent Child) using a tableView and Realm - ios

Question

I am trying to create a one to many relationship, otherwise known as a parent child relationship, in realm. I looked at the documentation that realm offers but I am still a little stuck on how to do the actual saving to realm. I have two views, the main view is a view controller that just has a tableview with the numbers 1-7. In this view i can mass select for editing these rows in the table and save them to realm. That part is no big deal.
On the next view I have something very similar where there is a tableview with just some sample data. There is a mass select rows button, that is fine, it is the save button that I am having trouble with. The data in this tableView, which is the same on all of them just for testing purposes, is data i want to have a child relationship with the data on the first view.
For example if I have 4 saved to realm I click the row with 4 on it and it takes me to my next View. The tableview on this has two rows and other data, but i want to be able to mass select these rows and save them as a child to 4. I am a little confused as to what the save to realm function would look like.
this is my first view controller
import UIKit
import Realm
import RealmSwift
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var tableView: UITableView!
var realm: Realm!
fileprivate var createSaves = SaveClass.createSaves()
var testingBool = false
var values: [String] = []
var valuesTwo: [String] = []
var valuesThree: [String] = []
#IBOutlet weak var itemBtn: UIBarButtonItem!
#IBOutlet weak var saveBtn: UIBarButtonItem!
override func viewDidLoad() {
super.viewDidLoad()
print(Realm.Configuration.defaultConfiguration.fileURL!)
realm = try! Realm()
self.tableView.delegate = self
self.tableView.dataSource = self
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return createSaves.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell
cell.txtLbl?.text = "\(createSaves[indexPath.row].label)"
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if testingBool == true {
values.append(createSaves[indexPath.row].label)
valuesTwo.append(createSaves[indexPath.row].romanNum)
valuesThree.append(createSaves[indexPath.row].txt)
} else if testingBool == false {
performSegue(withIdentifier: "segue", sender: indexPath)
}
}
func tableView(_ tableView: UITableView, didDeselectRowAt indexPath: IndexPath) {
if testingBool == true {
if let index = values.index(of: createSaves[indexPath.row].label) {
values.remove(at: index)
}
if let index = valuesTwo.index(of: createSaves[indexPath.row].romanNum) {
valuesTwo.remove(at: index)
}
if let index = valuesThree.index(of: createSaves[indexPath.row].txt) {
valuesThree.remove(at: index)
}
}
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let nxtVC = segue.destination as? TestingViewController
let myIndexPath = self.tableView.indexPathForSelectedRow!
let row = myIndexPath.row
nxtVC?.realmedData = createSaves[row].label
}
#IBAction func btnPressed(_ sender: Any) {
testingBool = !testingBool
if testingBool == true {
tableView.allowsMultipleSelection = true
tableView.allowsMultipleSelectionDuringEditing = true
itemBtn.title = "cancel"
} else if testingBool == false {
tableView.allowsMultipleSelection = false
tableView.allowsMultipleSelectionDuringEditing = false
itemBtn.title = "item"
}
}
#IBAction func saveBtnPressed(_ sender: Any) {
if testingBool == true {
//favorite(label: values)
realmed(label: values, romanNum: valuesTwo, txt: valuesThree)
}
}
func realmed(label: [String], romanNum: [String], txt: [String]) {
try? realm!.write {
for (stringOne, (stringTwo, stringThree)) in zip(label, zip(romanNum, txt)) {
let realmed = Realmed(label: stringOne, romanNum: stringTwo, txt: stringThree)
realm.add(realmed)
}
}
}
}
this is my second view
import UIKit
import Realm
import RealmSwift
class TestingViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var mainLbl: UILabel!
var realm: Realm!
var realmedData = ""
var testingBool = false
var values: [String] = []
var valuesTwo: [String] = []
#IBOutlet weak var testTable: UITableView!
#IBOutlet weak var selectBtn: UIButton!
#IBOutlet weak var saveBtn: UIButton!
let firstSave = OtherSave.otherArrOne()
override func viewDidLoad() {
super.viewDidLoad()
realm = try! Realm()
self.testTable.delegate = self
self.testTable.dataSource = self
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if objectExists(label: realmedData) == true {
self.mainLbl.text = "\(realmedData)"
} else {
self.mainLbl.text = "Don't Know"
}
}
#IBAction func selectBtnPressed(_ sender: Any) {
testingBool = !testingBool
if testingBool == true {
testTable.allowsMultipleSelection = true
testTable.allowsMultipleSelectionDuringEditing = true
} else if testingBool == false {
testTable.allowsMultipleSelection = false
testTable.allowsMultipleSelectionDuringEditing = false
}
}
#IBAction func saveBtnPressed(_ sender: Any) {
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return firstSave.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell2", for: indexPath) as! TestingTableViewCell
cell.nameLbl.text = "\(firstSave[indexPath.row].name)"
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if testingBool == true {
values.append(firstSave[indexPath.row].info)
valuesTwo.append(firstSave[indexPath.row].name)
}
}
func tableView(_ tableView: UITableView, didDeselectRowAt indexPath: IndexPath) {
if testingBool == true {
if let index = values.index(of: firstSave[indexPath.row].info) {
values.remove(at: index)
}
if let index = valuesTwo.index(of: firstSave[indexPath.row].name) {
valuesTwo.remove(at: index)
}
}
}
func fetchingLabel(label: String) -> Realmed? {
let realm = try? Realm()
return realm?.object(ofType: Realmed.self, forPrimaryKey: label)
}
func objectExists(label: String) -> Bool {
return realm.object(ofType: Realmed.self, forPrimaryKey: label) != nil
}
}
this is the parent's realm object:
import Foundation
import Realm
import RealmSwift
class Realmed: Object {
#objc dynamic var label = ""
#objc dynamic var romanNum = ""
#objc dynamic var txt = ""
let realmTwo = List<RealmTwo>()
override static func primaryKey() -> String {
return "label"
}
convenience init(label: String, romanNum: String, txt: String) {
self.init()
self.label = label
self.romanNum = romanNum
self.txt = txt
}
}
this is the child's realm object
import Foundation
import UIKit
import Realm
import RealmSwift
class RealmTwo: Object {
#objc dynamic var spanish = String()
#objc dynamic var french = String()
let realmed = LinkingObjects(fromType: Realmed.self, property: "realmTwo")
}
I have tried to do a function similar to the first view controllers:
func realmed(label: [String], romanNum: [String], txt: [String]) {
try? realm!.write {
for (stringOne, (stringTwo, stringThree)) in zip(label, zip(romanNum, txt)) {
let realmed = Realmed(label: stringOne, romanNum: stringTwo, txt: stringThree)
realm.add(realmed)
}
}
}
but I don't really understand how to create an instance of the data that i want to save as an array.
If there is anything i can help with, please ask
Thank you

Answer 1

I assume you want to create “RealmTwo” objects from “values” and “valuesTwo” and add them to a Realmed object .
What you want to do is
Fetch a parent object (Realmed)
Create a child object (RealmTwo)
Append the child to the parent object
You can do that with a function like this.
func save() {
let realmed = fetchingLabel(label: realmedData)! // fetch a parent
do {
try realm.write {
for index in 0..<values.count {
let realmTwo = RealmTwo() // create a child
realmTwo.french = values[index]
realmTwo.spanish = valuesTwo[index]
realmed.realmTwo.append(realmTwo) // append
}
}
} catch {
}
}