How to update existing value on realm database swift?

Question

I want to make any row from 'false' to 'true' or vice versa depending on table view did select and did deselect method. That mean's I need to update the existing value. How to do that. My code is not working it's creating another row instead of updating the existing one.

Here is the table

Here is the model

import UIKit
import RealmSwift

class TodoData: Object {

    @objc dynamic var todos: String = String()
    @objc dynamic var times: String = String()
    @objc dynamic var rows: Bool = Bool()

}

Here is the code I wrote for updating the value of the existing row:

    let data = TodoData()

            do {
                try realm.write {
                    data.rows = true
                    realm.add(data)
                }
            } catch let error as NSError {
                print(error.localizedDescription)
            }

Answer 1

Your code is not updating existing data. It is creating a new ToDoData and inserting it.

You want to fetch an existing ToDoData and update in write . Here is an example.

let todos = "a"
guard let data = realm.objects(ToDoData.self).filter("todos == %@", todos).first else { return }
try! realm.write {
    data.rows = true
}

Answer 2

If you literaly want to:

I want to make any row from 'false' to 'true' or vice versa

Here's the code that will make all false rows true, and all true row false.

let toDoResults = realm.objects(TodoData.self)
for toDo in toDoResults {
    try! realm.write {
        toDo.rows = !toDo.rows
    }
}

I think though, you just want to toggle a row when the user makes a change in your tableView.

let selectedTodo = "a"
let results = realm.objects(TodoData.self).filter("todos == %@", selectedTodo)
if let thisTodo = results.first {
   try! realm.write {
      thisTodo.rows = !thisTodo.rows //will toggle from t to f and from f to t
   }
}