How to get values from a relationship in core data (swift)

Question

I have a Entity named "Users" with 2 attributes named "username" and "password".

I have another Entity named "Info" with 4 attributes named "avatar", "level", "loss", "win".

I have a relationship setup with the "User" entity named "userInfo" Destination: "Info" Inverse: "userDetails"

I have a relationship setup with the "Info" entity named "userDetails" Destination: "Users" Inverse: "userInfo"

Here is my code right now:

@IBAction func loginButtonPressed(_ sender: UIButton) {

    // getting the inputs from the user
    let username = usernameField.text!
    let userPassword = passwordField.text!

    // creating a request to fetch the results for the users
    let context = appDelegate.persistentContainer.viewContext
    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")
    request.returnsObjectsAsFaults = false



    // now getting all the results
    do
    {
        // saving results in results
        let results = try context.fetch(request)


        // now checking if there is any results
        if results.count > 0
        {
            // creating a for loop to go through the results
            for result in results as! [NSManagedObject]
            {
                // checking if username and password match
                if username == (result.value(forKey: "username") as? String)! && userPassword == (result.value(forKey: "password") as? String)!
                {
                    // if they do set "isLoggedIn" to true
                    UserDefaults.standard.set(true, forKey:"isLoggedIn")
                    UserDefaults.standard.synchronize()


                    // Now saving the username and info of the user to the main viewController to display the users data later

                    // I NEED TO SAVE FROM THE RELATIONSHIP DATA HERE

                    // dismissing this view to go to the main view
                    self.dismiss(animated: true, completion: nil)
                }
                else
                {
                    // if username and passwords dont match then display it to the user.
                    alertMessage(userMessage: "Login failed username or password do not match!")
                }
            }
        }
        else
        {
            // if no results then display error message
            alertMessage(userMessage: "Login Failed: No users registered!")
        }
    }
    catch
    {
        // catch
    }
}

after checking the if the username and password are correct I need to store the data from the relationship of that username and password to 4 variables. Named: win, loss, level, and avatar.

I am confused on how to get the correct data from the relationship

I've tried using the "result" variable to try to get this but no luck.

Thanks

It looks like you have a pyramid of doom. 😭 You might want to learn to use guards: medium.com/the-traveled-ios-developers-guide/… — GetSwifty
@PEEJWEEJ project due tomorrow just need to get the data. Anyway I can do it? — JOhn

Scott Thompson Scott Thompson · Accepted Answer · 2017-05-02T20:11:46

One would generally create classes that represent the entities instead of working with the entities directly as NSManagedObjects so that seems a little odd. But you should be able to use setValueForKey:

result.setValue(/* whatever */, forKey: "userInfo.avatar")

How to get values from a relationship in core data (swift)

1 Answers