Question

我正在尝试从当前登录的用户中检索特定数据。我的数据库中的数据如下所示：

enter image description here

例如，我想抓取full_name并将其保存在变量userName中。以下是我用来获取数据的内容

ref.queryOrderedByChild("full_name").queryEqualToValue("userIdentifier").observeSingleEventOfType(.ChildAdded, withBlock: { snapshot in
            print(snapshot.value)
            // let userName = snapshot.value["full_name"] as! String
        })

不幸的是，这就是我的控制台打印的内容。

enter image description here

我将不胜感激任何帮助:)谢谢！

Answer 1

它会向您发出警告消息indexOn，因为您正在进行查询。

您应该通过.indexOn定义要编入索引的键您的安全和Firebase规则中的规则。虽然你被允许在客户端上临时创建这些查询，你会看到很多使用.indexOn时提高了性能

如您所知，您可以直接转到该节点，无需查询。

    let ref:FIRDatabaseReference! // your ref ie. root.child("users").child("stephenwarren001@yahoo.com")

    // only need to fetch once so use single event

    ref.observeSingleEventOfType(.Value, withBlock: { snapshot in

        if !snapshot.exists() { return }

        //print(snapshot)

        if let userName = snapshot.value["full_name"] as? String {
            print(userName)
        }
        if let email = snapshot.value["email"] as? String {
            print(email)
        }

        // can also use
        // snapshot.childSnapshotForPath("full_name").value as! String
    })

Answer 2

Swift 4

let ref = Database.database().reference(withPath: "user")
    ref.observeSingleEvent(of: .value, with: { snapshot in

        if !snapshot.exists() { return }

        print(snapshot) // Its print all values including Snap (User)

        print(snapshot.value!)

        let username = snapshot.childSnapshot(forPath: "full_name").value
        print(username!)

    })

Answer 3

{
    "rules": {
         "tbl_name": {
            ".indexOn": ["field_name1", "field_name2"]
         },
    ".read": true,
    ".write": true
    }
}

您可以在任何字段上应用indexOn。在规则安全性和规则选项卡中添加此json。希望这对你有用。：）

Answer 4

它检索登录的用户数据：

let ref = FIRDatabase.database().reference(fromURL: "DATABASE_URl")
let userID = FIRAuth.auth()?.currentUser?.uid
let usersRef = ref.child("users").child(userID!).observeSingleEvent(of: .value, with: { (snapshot) in
print(snapshot)

Answer 5

let ref = Database.database().reference().child("users/stephenwarren001@yahoo.com")


    ref.observeSingleEvent(of: .value, with: { (snap : DataSnapshot)  in

        print("\(String(describing:  snap.value))")


    }) { (err: Error) in


        print("\(err.localizedDescription)")

    }

Answer 6

    var refDatabase = DatabaseReference()

    refDatabase = Database.database().reference().child("users");
 let refUserIdChild = refDatabase.child("stephenwarren001@yahoo.com")
                    
                    refUserIdChild.observeSingleEvent(of: .value, with: { snapshot in

                        if !snapshot.exists() { return }

                        print(snapshot) // Its print all values including Snap (User)

                        print(snapshot.value!)
                        

                    if let tempDic : Dictionary = snapshot.value as? Dictionary<String,Any>
                    {
                           
                            if let userName = tempDic["full_name"] as? String {
                                  self.tfName.text = userName

                              }

                            if let email = tempDic["email"] as? String {
                                    self.tfEmail.text  = email

                              }

                           
                    }


                    })

Firebase在Swift中检索数据

6 个答案: