Firebase（NoSQL）：非规范化与索引 [英] Firebase (NoSQL): Denormalization vs Indexing

问题描述

假设我想写一个博客应用程序。我应该更喜欢以下两种选择之一吗？我宁愿拥有尽可能多的单一真相源，但我仍然不确定这种偏好是否来自我在SQL中的背景。

选项1（反规范化）：

 文章：{
 post_1：{
 title： hello，
 body：hi there！，
 uid：user_1，
评论：{
 comment_1：{
 body：hi I am comment ，
 uid：user_2，
}，
 comment_2：{
 body：bye I commented，
 uid：user_2，
 
 
 
 
 $ b用户：{
 user_1：{
 uid：user_1，
 post_1：{
 title：hello，
 body：hi there！，
 uid：user_1，
评论：{
 comment_1：{
 body：hi I commented，
 uid：user_2，
}，
 comment_2：{
 body：bye I commented，
 uid：user_2，
 }，
} 
} 
} 
} 
  

选项2（索引）：

$ p $ 文章：{
post_1：{
title：hello ，
body：hi there！，
uid：user_1，
authorName：Richard，
评论：{
comment_1：true，
comment_2：true
}
}
}

用户：{
user_1：{
uid：user_1，
displayName：Richard，
email：[e-mail]，
文章：{
post_1：true
}，
评论：{
comment_1：true，
comment_2：true
}
}
}

评论：{
comment_1：{
body：hi我评论过，
uid：user_1，
}，
comment_2：{
body：bye I commented，
uid： user_1，
}，
}


我想我应该选择2。

我在选项1中看到的主要问题是：一个数据来源太多。比方说，我想扩展应用程序，使每个帖子属于某个类别或标签。然后，我将不得不在 / categories / category_id 下面写 post / posts 和 / users / uid 。当帖子更新后，我必须记得在三个不同的地方修改帖子对象。如果我去选择2，我没有这个问题，因为只有一个来源的数据。

我缺少什么？

参考文献：

1. Firebase数据结构和网址
   
2. https://firebase.google.com/docs/database/web/structure-data

解决方案

第二个选项是更好的，否则你会迫使用户下载所有的评论和帖子（可以很多）。 >

您可以查看文档这里。

您可以处理重复操作在多个位置进行原子写入。

Assume that I want to write a blogging app. Should I prefer one of the following two options? I would prefer to have as much "single source of truth" as possible, but I am still not sure whether that preference comes from my background in SQL.

Option 1 (Denormalization):

Posts: {
  post_1: {
    title: "hello",
    body: "hi there!",
    uid: "user_1",
    comments: {
      comment_1: {
        body: "hi I commented",
        uid: "user_2",
      },
      comment_2: {
        body: "bye I commented",
        uid: "user_2",
      },
    }
  }
}

Users: {
  user_1: {
    uid: "user_1",
    post_1: {
      title: "hello",
      body: "hi there!",
      uid: "user_1",
      comments: {
        comment_1: {
          body: "hi I commented",
          uid: "user_2",
        },
        comment_2: {
          body: "bye I commented",
          uid: "user_2",
        },
      }
    }
  }
}

Option 2 (Indexing):

Posts: {
  post_1: {
    title: "hello",
    body: "hi there!",
    uid: "user_1",
    authorName: "Richard",
    comments: {
      comment_1: true,
      comment_2: true
    }
  }
}

Users: {
  user_1: {
    uid: "user_1",
    displayName: "Richard",
    email: "[e-mail]",
    posts: {
      post_1: true
    },
    comments: {
      comment_1: true,
      comment_2: true
    }
  }
}

Comments: {
  comment_1: {
    body: "hi I commented",
    uid: "user_1",
  },
  comment_2: {
    body: "bye I commented",
    uid: "user_1",
  },
}

I think I should prefer option 2.

The main problem that I see with option 1 is that there are too many sources for one data. Let's say I want to extend the app so each post belongs to a certain category or tag. Then, I will have to write a post object under /categories/category_id in addition to /posts and /users/uid. When the post gets updated, I have to remember to modify the post object in three different places. If I go with option 2, I don't have this problem because there's only one source for data.

Am I missing anything?

References:

1. Firebase data structure and url
2. https://firebase.google.com/docs/database/web/structure-data

解决方案

The second option is better because otherwise you would be forcing the user to download all the comments and posts (that can be a lot).

You can check in the documentation here.

And you can handle the duplication doing atomic writes across multiple locations.

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