Information_schema in mysql (similar to the system table in SQL) and mysqlschema

Information_schema in mysql (similar to the system table in SQL) and mysqlschema

Information_schema database table description:

SCHEMATA table: Provides information about all databases in the current mysql instance. Is the result of show databases.

TABLES Table: Provides information about TABLES in the database (including views ). Describes in detail the schema, table type, table engine, and creation time of a table. Is the result of show tables from schemaname.

COLUMNS table: Provides column information in the table. Describes all the columns of a table and the information of each column in detail. Is the result of show columns from schemaname. tablename.

STATISTICS table: Provides information about table indexes. Is the result of show index from schemaname. tablename.

USER_PRIVILEGES (user permission) Table: Provides information about full-process permissions. This information is from the mysql. user authorization table. Non-standard table.

SCHEMA_PRIVILEGES (scheme permission) Table: provides information about the scheme (database) permission. This information is from the mysql. db authorization table. Non-standard table.

TABLE_PRIVILEGES table: Lists table permissions. This information is from the mysql. tables_priv authorization table. Non-standard table.

COLUMN_PRIVILEGES (column permission) Table: provides information about the column permission. This information is derived from the mysql. columns_priv authorization table. Non-standard table.

CHARACTER_SETS table: Provides information about available character sets of mysql instances. This table is obtained from the show character set result SET.

COLLATIONS table: Provides control information about each character set.

COLLATION_CHARACTER_SET_APPLICABILITY table: Specifies the character set that can be used for verification. These columns are equivalent to the first two display fields of show collation.

TABLE_CONSTRAINTS table: Describes tables with constraints. And the constraint type of the table.

KEY_COLUMN_USAGE table: Describes the restricted key columns.

ROUTINES table: Provides information about stored subroutines (stored programs and functions. In this case, the ROUTINES table does not contain udfs ). The column named "mysql. proc name" specifies the mysql. proc table column corresponding to the INFORMATION_SCHEMA.ROUTINES table.

VIEWS table: displays information about VIEWS in the database. You must have the show views permission. Otherwise, you cannot view information.

TRIGGERS table: provides information about the trigger program. You must have the super permission to view the table.