ios - 为什么它会覆盖数据而不是在 firebase 中添加更多数据？

Question

我很想知道为什么当用户输入新数据时数据会被覆盖， 我希望它向它添加更多数据而不是覆盖它的数据 也想知道怎么读 提前谢谢你

 let oDB = Database.database().reference().child("Data")
    let oDictionary = ["Data1" : strange.text! , "Data2" : stranger.text!]
    let uid = Auth.auth().currentUser?.uid
    oDB.child(uid!).setValue(oDictionary) {

        (error, reference) in
        if error != nil{
            print(error!)
        } else  {
            print("saved Sucessfully")
            self.navigationController?.popViewController(animated: true)

        }
    }

 //In another ViewController
 func updateRequest() {
    let uid = Auth.auth().currentUser?.uid
    let yDb = Database.database().reference().child("Data").child(uid!)
    postDb.observeSingleEvent(of: .value) { (snapShot) in
        if let snapShotValue = snapShot.value as? Dictionary<String, String> {

        let text = snapShotValue["Data1"]!
        let case = snapShotValue["Data2"]!


        let data = Data()
        data.s= text
        data.y = case

        self.array.append(data)
        self.table.reloadData()
    }
    }
}

Answer 1

setValue 覆盖旧内容，你可能需要childByAutoId

oDB.child(uid!).childByAutoId().setValue(oDictionary) {

    (error, reference) in
    if error != nil{
        print(error!)
    } else  {
        print("saved Sucessfully")
        self.navigationController?.popViewController(animated: true)

    }

这将给出这个结构

Data 
  > uid
    > someKey1             <<<< auto generated 
        Data1:"---"
        Data2:"---"
    > someKey2             <<<< auto generated 
        Data1:"---"
        Data2:"---"

---

阅读

 //In another ViewController
 func updateRequest() {
    let uid = Auth.auth().currentUser?.uid
    let yDb = Database.database().reference().child("Data").child(uid!)
    postDb.observeSingleEvent(of: .value) { (snapShot) in
        if let snapShotValue = snapShot.value as? [String:[String:String]] {

          Array(snapShotValue.values).forEach {
            let data = Data()
            data.s= $0["Data1"]!
            data.y = $0["Data2"]! 
            self.array.append(data)
         }

        self.table.reloadData()
    }
    }
}