跨多个节点的Firebase数据一致性 [英] Firebase data consistency across multiple nodes

问题描述

根据火力点文档的数据是平坦的和索引用于链接树中的不同节点：$ b​​
$ b $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $
$ $ widgetId
widgets
$ widgetId

在上面的例子中，如果一个用户创建一个小部件， widgetid 也存储在用户节点下。

我的问题是有没有办法保证操作的一致性，考虑到现在有多个写需要。

假设第一个操作是：
$ b $ {p var newKey = fb.child（'widgets'）。push（{name：'widge'}）.key（）;

然后我可以把它写到：

$ p $ fb.child（'users'）。child（auth .id）.child（'widgets'）。child（newKey）.set（true）;

但是如果发生故障或其他问题他们之间的两个写道？或者，如果我有多个地方我需要存储该密钥，并在这些写入之间发生故障？

目前有一种方法来处理这个在firebase？如果没有，是否有计划在未来支持这一点？

如果是这样，有人可以提供一个具体的例子是如何做到的？

解决方案

请注意，这是Firebase核心API的一部分。有关详细信息，请参阅此博客文章。

  var mergedUpdate = {}; 
 mergedUpdate ['users /'+ userId +'/ widgets /'+ widgetId] = true; 
 mergedUpdate ['widgets /'+ widgetId] = widgetData; 
 
 var ref = new Firebase（https：//< YOUR-FIREBASE-APP> .firebaseio.com /）; 
 ref.update（mergedUpdate）; 
  

According to the firebase docs data is flattened and indices are used to link different nodes in the tree:

users
  $userId
    widgets
      $widgetId
widgets
  $widgetId

In the above example, if a user creates a widget, that widgetid is also stored under the user node.

My question is whether there is a way to guarantee the consistency of the operation, considering there is now the more than one write required.

Assuming the first operation is:

var newKey = fb.child('widgets').push({ name: 'widge' }).key();

I can then write it to:

fb.child('users').child(auth.id).child('widgets').child(newKey).set(true);

But what if there was a failure or other problem between the two writes? Or if I have multiple places I need to store that key and a failure occurs between those writes?

Is there currently a way to handle this in firebase?

If not, are there plans to support this in the future?

And if so, can someone provide a specific example of how that would be done?

解决方案

Note that this is now part of the core Firebase API. See this blog post for details.

var mergedUpdate = {};
mergedUpdate[ 'users/' + userId + '/widgets/' + widgetId ] = true;
mergedUpdate[ 'widgets/' + widgetId ] = widgetData;

var ref = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com/");
ref.update(mergedUpdate);

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