Firebase更新数据无效 [英] Firebase update data not working

问题描述

您好我想更新firebase数据，但是当我更新它插入到一个新的数据，而不是更新我设置的具体数据，这是'hoo'的姓氏

Hi I wanted to update the firebase data, but when I update it insert to a new data instead of updating the specific data that I set which is the lastname equal to 'hoo'

fb.orderByChild("Lastname").equalTo('hoo').once("value", function(snapshot){
  console.log(snapshot.ref());
  console.log(snapshot.val());
  // var snapref = snapshot.ref();
  snapshot.ref().update({
    FirstName: 'yoyo1'  
  });
})

编辑：

fb.orderByChild("Lastname").equalTo('hoo').once("child_added", function(snapshot){
    console.log(snapshot.ref());
    console.log(snapshot.val());
    // var snapref = snapshot.ref();
    snapshot.ref().update({
      FirstName: 'yoyo1'      
    });  
  })

使用'child_added'当您针对Firebase数据库执行查询时，可能会有潜在的潜在威胁，而不是使用值 。

推荐答案

是多个结果。所以快照包含了这些结果的列表。即使只有一个结果，快照将包含一个结果列表。

When you execute a query against the Firebase Database, there will potentially be multiple results. So the snapshot contains a list of those results. Even if there is only a single result, the snapshot will contain a list of one result.

这意味着当您调用 snapshot.ref（ ），你可以得到你所查询位置的引用（ fb ）不是。

This means that when you call snapshot.ref(), you get the reference to the location that you queried (fb) not to the child that you selected.

解决方法是循环结果：

The solution is to loop over the results:

fb.orderByChild("Lastname").equalTo('hoo').once("child_added", function(snapshot){
    snapshot.forEach(function(child) {
        child.ref().update({
            FirstName: 'yoyo1'      
        });  
    }
})

顺便说一下，我很确定我在过去几天给出了完全相同的答案，所以我强烈建议潜伏在 firebase-database 标签和学习，当你读到别人的奋斗。

By the way, I'm pretty sure I gave the exact same answer in the past few days. So I highly recommend lurking on the firebase-database tag and learning while you read what others struggle with.

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