如何在評估中檢索評估者的數據？

Question

我目前有問題。我是Firebase新手。我只想檢索組（來自評估），評論和總計（來自評估者）。但問題是它不起作用。這裏是我的JSON文件

{ 
"Evaluation" : { 
"-Kk8jZeZHW1s_zoTftcE" : { 
    "Evaluator" : { 
    "Y4WQjEH8c2SXYgphZTbOkSAg6272" : { 
     "comment" : "good", 
     "total" : 100, 
     "username" : "dr z" 
    } 
    }, 
    "group" : "Survivor", 
    "leader" : "chloe", 
    "lect1" : "v@gmail.com", 
    "lect2" : "s@yahoo.com", 
    "posterID" : "58", 
    "school" : "sds", 
    "title" : "Atomic2", 

}, 

這裏是我的try.js

var ref = firebase.database().ref("Evaluation"); 
ref.once('value', function(Evaluationsnapshot) { 
var Evaluationchild = Evaluationsnapshot.child("Evaluation").key; 
var Evaluatorchild = firebase.database().ref('Evaluation/' + Evaluationchild 
+ '/Evaluator'); 

Evaluationsnapshot.child(Evaluationchild).child('Evaluator').child(Evaluator 
child).forEach(function(Evaluatorchildsnapshot) { 
    console.log(Evaluatorchildsnapshot.key); 
    var commentdata = Evaluatorchildsnapshot.val().comment; 
    var totaldata = Evaluatorchildsnapshot.val().total; 
    var userdata = Evaluatorchildsnapshot.val().username; 

    console.log(" comment:" + commentdata + " total:" + totaldata + " 
    username:" + userdata); 

    }); 
}); 

迫切需要help.Please幫助me.Any反饋，不勝感激。

Answer 1

重構了一下你的代碼，這可能對你有幫助。

var ref = firebase.database().ref('Evaluation'); 
ref.on('value', function(snapshot) { 
    var records = snapshot.val(); 
    var recordKeys = Object.keys(records); 
    recordsKeys.forEach(function(recordKey) { 
    var groupName = records[recordKey].group; 
    var groupData = records[recordKey].total; 
    console.log(groupName + " was " + groupData); 
    }); 
});