MySql 中文参考指南

Chapter 16 MySQL Data Dictionary

目录

Table of Contents

MySQL Server 集成了一个事务数据字典，其中存储了有关数据库对象的信息。在以前的 MySQL 发行版中，字典数据存储在元数据文件、非事务表和存储引擎特定的数据字典中。

MySQL Server incorporates a transactional data dictionary that stores information about database objects. In previous MySQL releases, dictionary data was stored in metadata files, nontransactional tables, and storage engine-specific data dictionaries.

本章介绍数据字典的主要功能、优点、使用差异和限制。如需了解数据字典功能的其他含义，请参阅 MySQL 9.0 Release Notes 中的 “数据字典说明” 部分。

This chapter describes the main features, benefits, usage differences, and limitations of the data dictionary. For other implications of the data dictionary feature, refer to the “Data Dictionary Notes” section in the MySQL 9.0 Release Notes.

MySQL 数据字典的优点包括：

Benefits of the MySQL data dictionary include:

  1. Simplicity of a centralized data dictionary schema that uniformly stores dictionary data. See Section 16.1, “Data Dictionary Schema”.

  2. Removal of file-based metadata storage. See Section 16.2, “Removal of File-based Metadata Storage”.

  3. Transactional, crash-safe storage of dictionary data. See Section 16.3, “Transactional Storage of Dictionary Data”.

  4. Uniform and centralized caching for dictionary objects. See Section 16.4, “Dictionary Object Cache”.

  5. A simpler and improved implementation for some INFORMATION_SCHEMA tables. See Section 16.5, “INFORMATION_SCHEMA and Data Dictionary Integration”.

  6. Atomic DDL. See Section 15.1.1, “Atomic Data Definition Statement Support”.