November 2021
Intermediate to advanced
410 pages
12h 1m
Chinese
Content preview from MongoDB权威指南（第3版）
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167
第 8 章
事务
事务是数据库中对处理的逻辑分组，每个组或事务可以包含一个或多个操作，比如跨多个
文档的读写操作。
MongoDB
支持跨多个操作
、集合、数据库、文档和分片的
ACID
事务。
本章介绍事务并会定义
ACID
对于数据库的意义
，重点介绍如何在应用程序中使用它们，
并会针对
MongoDB
事务调优提供一些技巧。本章主要内容如下：
•
什么是事务；
•
如何使用事务；
•
对应用程序的事务限制进行调优。
8.1
事务简介
如上所述，事务是数据库中处理的逻辑单元，包括一个或多个数据库操作，既可以是读操
作，也可以是写操作。在某些情况下，作为这个逻辑处理单元的一部分，应用程序可能需
要对多个文档（在一个或多个集合中）进行读写。事务的一个重要方面是它永远不会只完
成一部分——它要么成功，要么失败。
要使用事务，你所部署的
MongoDB
必须是
MongoDB 4.2
或更高版本，
MongoDB
的驱动程序必须更新为
MongoDB 4.2
或更高版本。
MongoDB
提供
了一个驱动程序兼容性参考页面，可以用来确保
MongoDB
驱动程序版本的
兼容性。
ACID
的定义
ACID
是一个“真正”事务所需要具备的一组属性集合。
ACID
是原子性（
atomicity
）、 一
致性（
consistency
）
、隔离性（
isolation
）和持久性（
durability
）的缩写。
ACID
事务可以保
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