标签无法从Firebase数据库更新

Question

我刚开始在iOS上使用Firebase Database。我已使用firebase为iOS完全设置了cocoaPods。但是，该文本不显示从数据库检索到的文本。它在运行后只是显示为空。我怎么了？

Screenshot of my Database

class AppreciationViewController: UIViewController {
    var ref: DatabaseReference!
    @IBOutlet weak var otherAppreciation: UILabel!
    @IBOutlet weak var support: UILabel!
    @IBOutlet weak var body: UILabel!
    @IBOutlet weak var contact: UILabel!
    @IBOutlet weak var body2: UILabel!
    @IBOutlet weak var dedication: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    ref = Database.database().reference(); ref.child("Appreciation").child("body2").observe(.value) { (snapshot) in
            let body2String = snapshot.value as? String
            self.body2.text = body2String
        }
        ref.child("Appreciation").child("contact").observe(.value) { (snapshot) in
            let contactString = snapshot.value as? String
            self.contact.text = contactString
        }
ref.child("Appreciation").child("dedication").observe(.value) { (snapshot) in
            let dedicationString = snapshot.value as? String
            self.dedication.text = dedicationString
        }
    ref.child("Appreciation").child("otherAppreciation").observe(.value) { (snapshot) in
            let otherAppreciationString = snapshot.value as? String
            self.otherAppreciation.text = otherAppreciationString

        }
        ref.child("Appreciation").child("body").observe(.value) { (snapshot) in
            let bodyString = snapshot.value as? String
            self.body.text = bodyString
        }
        ref.child("Appreciation").child("support").observe(.value) { (snapshot) in
            let supportString = snapshot.value as? String
            self.support.text = supportString
        }
    }

}