ios - Firebase 在 Swift 中检索数据

Question

我正在尝试从当前登录的用户那里检索特定数据。我的数据库中的数据如下所示:

例如，我只想获取全名并将其保存在变量 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，这是我的控制台打印的内容。

如果有任何帮助，我将不胜感激 :) 谢谢!

Answer 1

它会向您显示警告消息 indexOn，因为您正在执行查询。

you should define the keys you will be indexing on via the .indexOn rule in your Security and Firebase Rules. While you are allowed to create these queries ad-hoc on the client, you will see greatly improved performance when using .indexOn

因为您知道要查找的名称，您可以直接转到该节点，而无需查询。

    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
    })