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MySQL之information_schema数据库详细讲解
来源:jb51  时间:2021/8/16 16:34:44  对本文有异议

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)

2. information_schema 库中常用的表

CHARACTER_SETS 表

提供了 mysql 可用字符集的信息。SHOW CHARACTER SET; 命令从这个表获取结果。

mysql> SHOW CHARACTER SET;
+----------+---------------------------------+---------------------+--------+
| Charset  | Description                     | Default collation   | Maxlen |
+----------+---------------------------------+---------------------+--------+
| big5     | Big5 Traditional Chinese        | big5_chinese_ci     |      2 |
| dec8     | DEC West European               | dec8_swedish_ci     |      1 |
| cp850    | DOS West European               | cp850_general_ci    |      1 |
...
| eucjpms  | UJIS for Windows Japanese       | eucjpms_japanese_ci |      3 |
| gb18030  | China National Standard GB18030 | gb18030_chinese_ci  |      4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.07 sec)

mysql> SELECT * FROM CHARACTER_SETS;
+--------------------+----------------------+---------------------------------+--------+
| CHARACTER_SET_NAME | DEFAULT_COLLATE_NAME | DESCRIPTION                     | MAXLEN |
+--------------------+----------------------+---------------------------------+--------+
| big5               | big5_chinese_ci      | Big5 Traditional Chinese        |      2 |
| dec8               | dec8_swedish_ci      | DEC West European               |      1 |
| cp850              | cp850_general_ci     | DOS West European               |      1 |
...
| eucjpms            | eucjpms_japanese_ci  | UJIS for Windows Japanese       |      3 |
| gb18030            | gb18030_chinese_ci   | China National Standard GB18030 |      4 |
+--------------------+----------------------+---------------------------------+--------+
41 rows in set (0.00 sec)

SCHEMATA 表

当前 mysql 实例中所有数据库的信息。SHOW DATABASES; 命令从这个表获取数据。

mysql> SELECT * FROM SCHEMATA;
+--------------+--------------------+----------------------------+------------------------+----------+
| CATALOG_NAME | SCHEMA_NAME        | DEFAULT_CHARACTER_SET_NAME | DEFAULT_COLLATION_NAME | SQL_PATH |
+--------------+--------------------+----------------------------+------------------------+----------+
| def          | information_schema | utf8                       | utf8_general_ci        | NULL     |
| def          | mysql              | latin1                     | latin1_swedish_ci      | NULL     |
| def          | performance_schema | utf8                       | utf8_general_ci        | NULL     |
| def          | sys                | utf8                       | utf8_general_ci        | NULL     |
| def          | test               | utf8                       | utf8_unicode_ci        | NULL     |
+--------------+--------------------+----------------------------+------------------------+----------+
10 rows in set (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test               |
+--------------------+
10 rows in set (0.00 sec)

TABLES 表

存储数据库中的表信息(包括视图),包括表属于哪个数据库,表的类型、存储引擎、创建时间等信息。SHOW TABLES FROM XX; 命令从这个表获取结果。

mysql> SELECT * FROM TABLES;
+---------------+--------------------+------------------------------------------------------+-------------+--------------------+---------+------------+------------+----------------+-------------+--------------------+--------------+-----------+----------------+---------------------+---------------------+---------------------+-------------------+----------+--------------------+--------------------------------------------+
| TABLE_CATALOG | TABLE_SCHEMA       | TABLE_NAME                                           | TABLE_TYPE  | ENGINE             | VERSION | ROW_FORMAT | TABLE_ROWS | AVG_ROW_LENGTH | DATA_LENGTH | MAX_DATA_LENGTH    | INDEX_LENGTH | DATA_FREE | AUTO_INCREMENT | CREATE_TIME         | UPDATE_TIME         | CHECK_TIME          | TABLE_COLLATION   | CHECKSUM | CREATE_OPTIONS     | TABLE_COMMENT                              |
+---------------+--------------------+------------------------------------------------------+-------------+--------------------+---------+------------+------------+----------------+-------------+--------------------+--------------+-----------+----------------+---------------------+---------------------+---------------------+-------------------+----------+--------------------+--------------------------------------------+
| def           | information_schema | CHARACTER_SETS                                       | SYSTEM VIEW | MEMORY             |      10 | Fixed      |       NULL |            384 |           0 |           16434816 |            0 |         0 |           NULL | 2018-04-23 11:51:32 | NULL                | NULL                | utf8_general_ci   |     NULL | max_rows=43690     |                                            |
| def           | information_schema | COLLATIONS                                           | SYSTEM VIEW | MEMORY             |      10 | Fixed      |       NULL |            231 |           0 |           16704765 |            0 |         0 |           NULL | 2018-04-23 11:51:32 | NULL                | NULL                | utf8_general_ci   |     NULL | max_rows=72628     |                                            |
...
| def           | zentao             | zt_usertpl                                           | BASE TABLE  | MyISAM             |      10 | Dynamic    |          0 |              0 |           0 |    281474976710655 |         1024 |         0 |              1 | 2017-08-16 16:36:45 | 2017-08-16 16:36:45 | NULL                | utf8_general_ci   |     NULL |                    |                                            |
+---------------+--------------------+------------------------------------------------------+-------------+--------------------+---------+------------+------------+----------------+-------------+--------------------+--------------+-----------+----------------+---------------------+---------------------+---------------------+-------------------+----------+--------------------+--------------------------------------------+
525 rows in set (3.03 sec)

mysql> SHOW TABLES FROM zentao;
+-------------------+
| Tables_in_zentao  |
+-------------------+
| zt_action         |
| zt_block          |
| zt_branch         |
...
| zt_usertpl        |
+-------------------+
48 rows in set (0.00 sec)

COLUMNS 表

存储表中的列信息,包括表有多少列、每个列的类型等。SHOW COLUMNS FROM schemaname.tablename 命令从这个表获取结果。

mysql> SELECT * FROM COLUMNS LIMIT 2,5;
+---------------+--------------------+----------------+--------------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+---------------+--------------------+--------------------+-----------------+-------------+------------+-------+------------+----------------+-----------------------+
| TABLE_CATALOG | TABLE_SCHEMA       | TABLE_NAME     | COLUMN_NAME        | ORDINAL_POSITION | COLUMN_DEFAULT | IS_NULLABLE | DATA_TYPE | CHARACTER_MAXIMUM_LENGTH | CHARACTER_OCTET_LENGTH | NUMERIC_PRECISION | NUMERIC_SCALE | DATETIME_PRECISION | CHARACTER_SET_NAME | COLLATION_NAME  | COLUMN_TYPE | COLUMN_KEY | EXTRA | PRIVILEGES | COLUMN_COMMENT | GENERATION_EXPRESSION |
+---------------+--------------------+----------------+--------------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+---------------+--------------------+--------------------+-----------------+-------------+------------+-------+------------+----------------+-----------------------+
| def           | information_schema | CHARACTER_SETS | DESCRIPTION        |                3 |                | NO          | varchar   |                       60 |                    180 |              NULL |          NULL |               NULL | utf8               | utf8_general_ci | varchar(60) |            |       | select     |                |                       |
| def           | information_schema | CHARACTER_SETS | MAXLEN             |                4 | 0              | NO          | bigint    |                     NULL |                   NULL |                19 |             0 |               NULL | NULL               | NULL            | bigint(3)   |            |       | select     |                |                       |
| def           | information_schema | COLLATIONS     | COLLATION_NAME     |                1 |                | NO          | varchar   |                       32 |                     96 |              NULL |          NULL |               NULL | utf8               | utf8_general_ci | varchar(32) |            |       | select     |                |                       |
| def           | information_schema | COLLATIONS     | CHARACTER_SET_NAME |                2 |                | NO          | varchar   |                       32 |                     96 |              NULL |          NULL |               NULL | utf8               | utf8_general_ci | varchar(32) |            |       | select     |                |                       |
| def           | information_schema | COLLATIONS     | ID                 |                3 | 0              | NO          | bigint    |                     NULL |                   NULL |                19 |             0 |               NULL | NULL               | NULL            | bigint(11)  |            |       | select     |                |                       |
+---------------+--------------------+----------------+--------------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+---------------+--------------------+--------------------+-----------------+-------------+------------+-------+------------+----------------+-----------------------+
5 rows in set (0.08 sec)

STATISTICS 表

表索引的信息。SHOW INDEX FROM schemaname.tablename; 命令从这个表获取结果。

mysql> SHOW INDEX FROM szhuizhong.users;
+-------+------------+---------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name      | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-------+------------+---------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| users |          0 | PRIMARY       |            1 | UserID      | A         |        1460 |     NULL | NULL   |      | BTREE      |         |               |
| users |          0 | Account_index |            1 | Account     | A         |        1460 |     NULL | NULL   |      | BTREE      |         |               |
| users |          1 | CorpID        |            1 | FromID      | A         |           2 |     NULL | NULL   | YES  | BTREE      |         |               |
+-------+------------+---------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
3 rows in set (0.00 sec)

USER_PRIVILEGES 表

用户权限表。内容源自 mysql.user 授权表。是非标准表。

mysql> SELECT * FROM USER_PRIVILEGES;
+-------------------------+---------------+-------------------------+--------------+
| GRANTEE                 | TABLE_CATALOG | PRIVILEGE_TYPE          | IS_GRANTABLE |
+-------------------------+---------------+-------------------------+--------------+
| 'mysql.sys'@'localhost' | def           | USAGE                   | NO           |
| 'root'@'%'              | def           | SELECT                  | YES          |
| 'root'@'%'              | def           | INSERT                  | YES          |
| 'root'@'%'              | def           | UPDATE                  | YES          |
| 'root'@'%'              | def           | DELETE                  | YES          |
| 'root'@'%'              | def           | CREATE                  | YES          |
| 'root'@'%'              | def           | DROP                    | YES          |
| 'root'@'%'              | def           | RELOAD                  | YES          |
| 'root'@'%'              | def           | SHUTDOWN                | YES          |
| 'root'@'%'              | def           | PROCESS                 | YES          |
| 'root'@'%'              | def           | FILE                    | YES          |
| 'root'@'%'              | def           | REFERENCES              | YES          |
| 'root'@'%'              | def           | INDEX                   | YES          |
| 'root'@'%'              | def           | ALTER                   | YES          |
| 'root'@'%'              | def           | SHOW DATABASES          | YES          |
| 'root'@'%'              | def           | SUPER                   | YES          |
| 'root'@'%'              | def           | CREATE TEMPORARY TABLES | YES          |
| 'root'@'%'              | def           | LOCK TABLES             | YES          |
| 'root'@'%'              | def           | EXECUTE                 | YES          |
| 'root'@'%'              | def           | REPLICATION SLAVE       | YES          |
| 'root'@'%'              | def           | REPLICATION CLIENT      | YES          |
| 'root'@'%'              | def           | CREATE VIEW             | YES          |
| 'root'@'%'              | def           | SHOW VIEW               | YES          |
| 'root'@'%'              | def           | CREATE ROUTINE          | YES          |
| 'root'@'%'              | def           | ALTER ROUTINE           | YES          |
| 'root'@'%'              | def           | CREATE USER             | YES          |
| 'root'@'%'              | def           | EVENT                   | YES          |
| 'root'@'%'              | def           | TRIGGER                 | YES          |
| 'root'@'%'              | def           | CREATE TABLESPACE       | YES          |
+-------------------------+---------------+-------------------------+--------------+
29 rows in set (0.00 sec)

SCHEMA_PRIVILEGES 表

方案权限表。给出了关于方案(数据库)权限的信息。内容来自 mysql.db 授权表。是非标准表。

mysql> SELECT * FROM SCHEMA_PRIVILEGES;
+-------------------------+---------------+--------------+-------------------------+--------------+
| GRANTEE                 | TABLE_CATALOG | TABLE_SCHEMA | PRIVILEGE_TYPE          | IS_GRANTABLE |
+-------------------------+---------------+--------------+-------------------------+--------------+
| 'mysql.sys'@'localhost' | def           | sys          | TRIGGER                 | NO           |
| 'root'@'%'              | def           | mysql        | SELECT                  | YES          |
| 'root'@'%'              | def           | mysql        | INSERT                  | YES          |
| 'root'@'%'              | def           | mysql        | UPDATE                  | YES          |
| 'root'@'%'              | def           | mysql        | DELETE                  | YES          |
| 'root'@'%'              | def           | mysql        | CREATE                  | YES          |
| 'root'@'%'              | def           | mysql        | DROP                    | YES          |
| 'root'@'%'              | def           | mysql        | REFERENCES              | YES          |
| 'root'@'%'              | def           | mysql        | INDEX                   | YES          |
| 'root'@'%'              | def           | mysql        | ALTER                   | YES          |
| 'root'@'%'              | def           | mysql        | CREATE TEMPORARY TABLES | YES          |
| 'root'@'%'              | def           | mysql        | LOCK TABLES             | YES          |
| 'root'@'%'              | def           | mysql        | EXECUTE                 | YES          |
| 'root'@'%'              | def           | mysql        | CREATE VIEW             | YES          |
| 'root'@'%'              | def           | mysql        | SHOW VIEW               | YES          |
| 'root'@'%'              | def           | mysql        | CREATE ROUTINE          | YES          |
| 'root'@'%'              | def           | mysql        | ALTER ROUTINE           | YES          |
| 'root'@'%'              | def           | mysql        | EVENT                   | YES          |
| 'root'@'%'              | def           | mysql        | TRIGGER                 | YES          |
+-------------------------+---------------+--------------+-------------------------+--------------+
19 rows in set (0.00 sec)

TABLE_PRIVILEGES 表

表权限表。给出了关于表权限的信息。内容源自 mysql.tables_priv 授权表。是非标准表。

mysql> SELECT * FROM TABLE_PRIVILEGES;
+-------------------------+---------------+--------------+------------+----------------+--------------+
| GRANTEE                 | TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME | PRIVILEGE_TYPE | IS_GRANTABLE |
+-------------------------+---------------+--------------+------------+----------------+--------------+
| 'mysql.sys'@'localhost' | def           | sys          | sys_config | SELECT         | NO           |
+-------------------------+---------------+--------------+------------+----------------+--------------+
1 row in set (0.00 sec)

COLUMN_PRIVILEGES 表

列权限表。给出了关于列权限的信息。内容源自 mysql.columns_priv 授权表。是非标准表。

mysql> SELECT * FROM COLUMN_PRIVILEGES;
Empty set (0.00 sec)

COLLATIONS 表

提供了关于各字符集的对照信息。SHOW COLLATION; 命令从这个表获取结果。

mysql> SELECT * FROM COLLATIONS;
+--------------------------+--------------------+-----+------------+-------------+---------+
| COLLATION_NAME           | CHARACTER_SET_NAME | ID  | IS_DEFAULT | IS_COMPILED | SORTLEN |
+--------------------------+--------------------+-----+------------+-------------+---------+
| big5_chinese_ci          | big5               |   1 | Yes        | Yes         |       1 |
| big5_bin                 | big5               |  84 |            | Yes         |       1 |
| dec8_swedish_ci          | dec8               |   3 | Yes        | Yes         |       1 |
| dec8_bin                 | dec8               |  69 |            | Yes         |       1 |
...
| gb18030_bin              | gb18030            | 249 |            | Yes         |       1 |
| gb18030_unicode_520_ci   | gb18030            | 250 |            | Yes         |       8 |
+--------------------------+--------------------+-----+------------+-------------+---------+
222 rows in set (0.03 sec)

COLLATION_CHARACTER_SET_APPLICABILITY 表

指明了可用于校对的字符集。相当于 SHOW COLLATION 命令结果的前两个字段。

mysql> SELECT * FROM COLLATION_CHARACTER_SET_APPLICABILITY;
+--------------------------+--------------------+
| COLLATION_NAME           | CHARACTER_SET_NAME |
+--------------------------+--------------------+
| big5_chinese_ci          | big5               |
| big5_bin                 | big5               |
| dec8_swedish_ci          | dec8               |
...
| gb18030_bin              | gb18030            |
| gb18030_unicode_520_ci   | gb18030            |
+--------------------------+--------------------+
222 rows in set (0.00 sec)

TABLE_CONSTRAINTS 表

描述了存在约束的表。以及表的约束类型。

mysql> SELECT * FROM TABLE_CONSTRAINTS;
+--------------------+-------------------+--------------------+--------------+---------------------------+-----------------+
| CONSTRAINT_CATALOG | CONSTRAINT_SCHEMA | CONSTRAINT_NAME    | TABLE_SCHEMA | TABLE_NAME                | CONSTRAINT_TYPE |
+--------------------+-------------------+--------------------+--------------+---------------------------+-----------------+
| def                | mysql             | PRIMARY            | mysql        | columns_priv              | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | db                        | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | engine_cost               | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | event                     | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | func                      | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | gtid_executed             | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | help_category             | PRIMARY KEY     |
| def                | mysql             | name               | mysql        | help_category             | UNIQUE          |
| def                | mysql             | PRIMARY            | mysql        | help_keyword              | PRIMARY KEY     |
| def                | mysql             | name               | mysql        | help_keyword              | UNIQUE          |
| def                | mysql             | PRIMARY            | mysql        | help_relation             | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | help_topic                | PRIMARY KEY     |
| def                | mysql             | name               | mysql        | help_topic                | UNIQUE          |
| def                | mysql             | PRIMARY            | mysql        | innodb_index_stats        | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | innodb_table_stats        | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | ndb_binlog_index          | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | plugin                    | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | proc                      | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | procs_priv                | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | proxies_priv              | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | server_cost               | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | servers                   | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | slave_master_info         | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | slave_relay_log_info      | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | slave_worker_info         | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | tables_priv               | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | time_zone                 | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | time_zone_leap_second     | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | time_zone_name            | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | time_zone_transition      | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | time_zone_transition_type | PRIMARY KEY     |
| def                | mysql             | PRIMARY            | mysql        | user                      | PRIMARY KEY     |
| def                | sys               | PRIMARY            | sys          | sys_config                | PRIMARY KEY     |
| def                | zentao            | PRIMARY            | zentao       | zt_action                 | PRIMARY KEY     |
...
| def                | zentao            | account            | zentao       | zt_usergroup              | UNIQUE          |
| def                | zentao            | PRIMARY            | zentao       | zt_userquery              | PRIMARY KEY     |
| def                | zentao            | PRIMARY            | zentao       | zt_usertpl                | PRIMARY KEY     |
+--------------------+-------------------+--------------------+--------------+---------------------------+-----------------+
213 rows in set (0.37 sec)

KEY_COLUMN_USAGE 表

描述了具有约束的键列。

mysql> SELECT * FROM KEY_COLUMN_USAGE;
+--------------------+-------------------+--------------------+---------------+--------------+---------------------------+--------------------+------------------+-------------------------------+-------------------------+-----------------------+------------------------+
| CONSTRAINT_CATALOG | CONSTRAINT_SCHEMA | CONSTRAINT_NAME    | TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME                | COLUMN_NAME        | ORDINAL_POSITION | POSITION_IN_UNIQUE_CONSTRAINT | REFERENCED_TABLE_SCHEMA | REFERENCED_TABLE_NAME | REFERENCED_COLUMN_NAME |
+--------------------+-------------------+--------------------+---------------+--------------+---------------------------+--------------------+------------------+-------------------------------+-------------------------+-----------------------+------------------------+
| def                | mysql             | PRIMARY            | def           | mysql        | columns_priv              | Host               |                1 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | columns_priv              | Db                 |                2 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | columns_priv              | User               |                3 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | columns_priv              | Table_name         |                4 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | columns_priv              | Column_name        |                5 |                          NULL | NULL                    | NULL                  | NULL                   |
...
| def                | mysql             | PRIMARY            | def           | mysql        | time_zone_leap_second     | Transition_time    |                1 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | time_zone_name            | Name               |                1 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | time_zone_transition      | Time_zone_id       |                1 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | time_zone_transition      | Transition_time    |                2 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | time_zone_transition_type | Time_zone_id       |                1 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | time_zone_transition_type | Transition_type_id |                2 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | user                      | Host               |                1 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | mysql             | PRIMARY            | def           | mysql        | user                      | User               |                2 |                          NULL | NULL                    | NULL                  | NULL                   |
| def                | sys               | PRIMARY            | def           | sys          | sys_config                | variable           |                1 |                          NULL | NULL                    | NULL                  | NULL                   |
+--------------------+-------------------+--------------------+---------------+--------------+---------------------------+--------------------+------------------+-------------------------------+-------------------------+-----------------------+------------------------+
278 rows in set (0.03 sec)

ROUTINES 表

提供了关于存储子程序(存储程序和函数)的信息。此时,ROUTINES 表不包含自定义函数(UDF)。名为“mysql.proc name”的列指明了对应于 INFORMATION_SCHEMA.ROUTINES 表的 mysql.proc 列。

VIEWS 表

给出了关于数据库中的视图的信息。需要有 show views 权限,否则无法查看视图信息。

mysql> SELECT * FROM VIEWS LIMIT 1\G
*************************** 1. row ***************************
       TABLE_CATALOG: def
        TABLE_SCHEMA: sys
          TABLE_NAME: host_summary
     VIEW_DEFINITION: select if(isnull(`performance_schema`.`accounts`.`HOST`),'background',`performance_schema`.`accounts`.`HOST`) AS `host`,sum(`stmt`.`total`) AS `statements`,`sys`.`format_time`(sum(`stmt`.`total_latency`)) AS `statement_latency`,`sys`.`format_time`(ifnull((sum(`stmt`.`total_latency`) / nullif(sum(`stmt`.`total`),0)),0)) AS `statement_avg_latency`,sum(`stmt`.`full_scans`) AS `table_scans`,sum(`io`.`ios`) AS `file_ios`,`sys`.`format_time`(sum(`io`.`io_latency`)) AS `file_io_latency`,sum(`performance_schema`.`accounts`.`CURRENT_CONNECTIONS`) AS `current_connections`,sum(`performance_schema`.`accounts`.`TOTAL_CONNECTIONS`) AS `total_connections`,count(distinct `performance_schema`.`accounts`.`USER`) AS `unique_users`,`sys`.`format_bytes`(sum(`mem`.`current_allocated`)) AS `current_memory`,`sys`.`format_bytes`(sum(`mem`.`total_allocated`)) AS `total_memory_allocated` from (((`performance_schema`.`accounts` join `sys`.`x$host_summary_by_statement_latency` `stmt` on((`performance_schema`.`accounts`.`HOST` = `stmt`.`host`))) join `sys`.`x$host_summary_by_file_io` `io` on((`performance_schema`.`accounts`.`HOST` = `io`.`host`))) join `sys`.`x$memory_by_host_by_current_bytes` `mem` on((`performance_schema`.`accounts`.`HOST` = `mem`.`host`))) group by if(isnull(`performance_schema`.`accounts`.`HOST`),'background',`performance_schema`.`accounts`.`HOST`)
        CHECK_OPTION: NONE
        IS_UPDATABLE: NO
             DEFINER: mysql.sys@localhost
       SECURITY_TYPE: INVOKER
CHARACTER_SET_CLIENT: utf8
COLLATION_CONNECTION: utf8_general_ci
1 row in set (0.03 sec)

TRIGGERS 表

提供了关于触发程序的信息。必须有 super 权限才能查看该表。

mysql> SELECT * FROM TRIGGERS LIMIT 1\G
*************************** 1. row ***************************
           TRIGGER_CATALOG: def
            TRIGGER_SCHEMA: sys
              TRIGGER_NAME: sys_config_insert_set_user
        EVENT_MANIPULATION: INSERT
      EVENT_OBJECT_CATALOG: def
       EVENT_OBJECT_SCHEMA: sys
        EVENT_OBJECT_TABLE: sys_config
              ACTION_ORDER: 1
          ACTION_CONDITION: NULL
          ACTION_STATEMENT: BEGIN IF @sys.ignore_sys_config_triggers != true AND NEW.set_by IS NULL THEN SET NEW.set_by = USER(); END IF; END
        ACTION_ORIENTATION: ROW
             ACTION_TIMING: BEFORE
ACTION_REFERENCE_OLD_TABLE: NULL
ACTION_REFERENCE_NEW_TABLE: NULL
  ACTION_REFERENCE_OLD_ROW: OLD
  ACTION_REFERENCE_NEW_ROW: NEW
                   CREATED: 2017-05-27 11:18:43.60
                  SQL_MODE: 
                   DEFINER: mysql.sys@localhost
      CHARACTER_SET_CLIENT: utf8
      COLLATION_CONNECTION: utf8_general_ci
        DATABASE_COLLATION: utf8_general_ci
1 row in set (0.00 sec)

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