Firebase DatabaseReference vs DataSnapshot [英] Firebase DatabaseReference vs DataSnapshot

问题描述

我不太明白什么时候应该使用DatabaseReference和DataSnapshot。

在我的应用程序中，我似乎没有真正区别使用它们（可能除了写入到Firebase，在这种情况下DataSnapshot没有被创建）。

解决方案

DatabaseReference是所有数据库操作的起点。这允许您读取，写入和创建新的DatabaseReferences。

DataSnapshot是在Firebase位置上高效生成的不可变数据副本。他们不能被修改，永远不会改变。

我相信，在DataSnapshot下创建一个比DatabaseReference更安全的对象，在一个只读的情况下，因为这将是一个不可变的对象，没有任何额外的数据附加到它像DatabaseReference。

来源：

DatabaseReference
https://firebase.google.com/docs/reference/android/com/google/firebase/database/DatabaseReference

DataSnapshot
< href =https://firebase.google.com/docs/reference/android/com/google/firebase/database/DataSnapshot =nofollow noreferrer> https://firebase.google.com/docs/reference / android / com / google / firebase / database / DataSnapshot

I did not quite understand when should I use DatabaseReference and when DataSnapshot.

In my application I seem to be using both of them without real distinction (maybe except for writing to Firebase in which case DataSnapshot was not made for).

解决方案

A DatabaseReference is a starting point for all database operations. This allows you to read, write, and create new DatabaseReferences.

A DataSnapshot is an efficiently-generated immutable copy of the data at a Firebase Location. They cannot be modified and will never change.

I believe that under the hood, the DataSnapshot would be a more efficient object to create than a DatabaseReference and a safer object to work with in a read-only scenario as this would be an immutable object without any extra data attached to it like the DatabaseReference.

Sources:

DatabaseReference https://firebase.google.com/docs/reference/android/com/google/firebase/database/DatabaseReference

DataSnapshot https://firebase.google.com/docs/reference/android/com/google/firebase/database/DataSnapshot

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