问信息是否未添加到实时数据库？

EN

import UIKit
import Firebase
import FirebaseDatabase



class addViewController: UIViewController {

var refrelation : DatabaseReference!

    @IBOutlet weak var relation: UITextField!
    @IBOutlet weak var dOB: UITextField!
    @IBOutlet weak var lastname: UITextField!
    @IBOutlet weak var firstName: UITextField!

    @IBAction func addName(_ sender: UIButton) {
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        refrelation = Database.database().reference().child("FirstName");
    }

    func addName() {
        let key = refrelation.childByAutoId().key
        let relationn = [ "id":key,"firstName": firstName.text! as String,
                          "lastname" : lastname.text! as String,
                          "Relation": relation.text! as String,
                          "DOB": dOB.text! as String]
        refrelation.child(key!).setValue(relationn)
    }