November 2021
Intermediate to advanced
410 pages
12h 1m
Chinese
Content preview from MongoDB权威指南（第3版）
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
3
第 1 章
MongoDB
简介
MongoDB
是功能强大、灵活且易于扩展的通用型数据库。它融合了二级索引、范围查询、
排序、聚合以及地理空间索引等诸多特性。本章介绍
MongoDB
的主要设计决策。
1.1
易于使用
MongoDB
不是关系数据库，而是
面向文档
（
document-oriented
）的数据库。便于扩展是
MongoDB
没有使用关系模型的主要原因，此外这样做还有一些其他优势。
面向文档的数据库使用更灵活的“文档”模型取代了“行”的概念。通过嵌入文档和数
组，面向文档的方式可以仅用一条记录来表示复杂的层次关系，这与使用现代面向对象语
言的开发人员思考数据的方式非常契合。
MongoDB
中也没有预定义模式
（
predefined schema
）：文档键值的类型和大小不是固定的。
由于没有固定的模式，因此按需添加或删除字段变得更容易。通常来说，因为开发人员可
以进行快速迭代，所以开发效率会更高，而且这也使实验更容易进行。开发人员可以尝试
多种数据模型，然后选择最好的一种。
1.2
易于扩展
应用程序的数据集大小正以惊人的速度在增长。可用带宽的增加和存储价格的下降，使得
即使是小规模的应用程序所需要存储的数据量，也超出了很多数据库的处理能力。
TB
级
别的数据量，过去听起来是天文数字，现在已经司空见惯了。
随着所需存储数据量的增长，开发人员面临一个艰难的决定：应该如何扩展数据库？这可
以归结为两种选择：纵向扩展（提高配置）和横向扩展（将数据分布到更多机器上）。纵
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.