MySQL之information_schema数据库详细讲解

1. 概述

information_schema 数据库跟 performance_schema 一样，都是 MySQL 自带的信息数据库。其中 performance_schema 用于性能分析，而 information_schema 用于存储数据库元数据(关于数据的数据)，例如数据库名、表名、列的数据类型、访问权限等。

information_schema 中的表实际上是视图，而不是基本表，因此，文件系统上没有与之相关的文件。

mysql> use information_schema;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+---------------------------------------+
| Tables_in_information_schema          |
+---------------------------------------+
| CHARACTER_SETS                        |
| COLLATIONS                            |
| COLLATION_CHARACTER_SET_APPLICABILITY |
| COLUMNS                               |
| COLUMN_PRIVILEGES                     |
| ENGINES                               |
| EVENTS                                |
| FILES                                 |
| GLOBAL_STATUS                         |
| GLOBAL_VARIABLES                      |
| KEY_COLUMN_USAGE                      |
| OPTIMIZER_TRACE                       |
| PARAMETERS                            |
| PARTITIONS                            |
| PLUGINS                               |
| PROCESSLIST                           |
| PROFILING                             |
| REFERENTIAL_CONSTRAINTS               |
| ROUTINES                              |
| SCHEMATA                              |
| SCHEMA_PRIVILEGES                     |
| SESSION_STATUS                        |
| SESSION_VARIABLES                     |
| STATISTICS                            |
| TABLES                                |
| TABLESPACES                           |
| TABLE_CONSTRAINTS                     |
| TABLE_PRIVILEGES                      |
| TRIGGERS                              |
| USER_PRIVILEGES                       |
| VIEWS                                 |
| INNODB_LOCKS                          |
| INNODB_TRX                            |
| INNODB_SYS_DATAFILES                  |
| INNODB_FT_CONFIG                      |
| INNODB_SYS_VIRTUAL                    |
| INNODB_CMP                            |
| INNODB_FT_BEING_DELETED               |
| INNODB_CMP_RESET                      |
| INNODB_CMP_PER_INDEX                  |
| INNODB_CMPMEM_RESET                   |
| INNODB_FT_DELETED                     |
| INNODB_BUFFER_PAGE_LRU                |
| INNODB_LOCK_WAITS                     |
| INNODB_TEMP_TABLE_INFO                |
| INNODB_SYS_INDEXES                    |
| INNODB_SYS_TABLES                     |
| INNODB_SYS_FIELDS                     |
| INNODB_CMP_PER_INDEX_RESET            |
| INNODB_BUFFER_PAGE                    |
| INNODB_FT_DEFAULT_STOPWORD            |
| INNODB_FT_INDEX_TABLE                 |
| INNODB_FT_INDEX_CACHE                 |
| INNODB_SYS_TABLESPACES                |
| INNODB_METRICS                        |
| INNODB_SYS_FOREIGN_COLS               |
| INNODB_CMPMEM                         |
| INNODB_BUFFER_POOL_STATS              |
| INNODB_SYS_COLUMNS                    |
| INNODB_SYS_FOREIGN                    |
| INNODB_SYS_TABLESTATS                 |
+---------------------------------------+
61 rows in set (0.00 sec)