-- show information about characterset，查询mysql的编码

 

SHOW VARIABLES LIKE '%char%';

 

 

 

-- show all relationships between tables   in database  your_databases;   查询数据库中的表之间的关联信息

 

select TABLE_NAME , COLUMN_NAME ,
REFERENCED_TABLE_NAME , REFERENCED_COLUMN_NAME 
from INFORMATION_SCHEMA.KEY_COLUMN_USAGE
where CONSTRAINT_SCHEMA = 'your_databases' and 
REFERENCED_TABLE_SCHEMA is not null and
REFERENCED_TABLE_NAME is not null and
REFERENCED_COLUMN_NAME is not null;

-- engines information

SHOW ENGINES;