SQL.Cookbook 读书笔记5 元数据查询

第五章 元数据查询 查询数据库本身信息 表结构 索引等

5.1 查询test库下的所有表信息

MYSQL

SELECT * from information_schema.`TABLES` WHERE TABLE_SCHEMA = 'test';

ORACLE

select table_name from all_tables where owner = 'test';

5.2 查询表中列的信息

MYSQL

SELECT * from information_schema.`COLUMNS` WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME = 'student';

ORACLE

select * from all_tab_columns where owner = 'test' and table_name = 'student';

5.3 列出表的索引

MYSQL

show index from emp;

ORACLE

select table_name,index_name,column_name,column_position from sys.all_ind_columns where table_name = 'emp' and table_owner = 'test';

5.4 列出表约束

ORACLE

select a.table_name,a.constraint_name,b.coulumn_name,a.constraint_type from all_constraints a,all_cons_columns b where a.table_name = 'EMP' and a.owner = 'test' and a.table_name = b.table_name and a. owner = b.owner and a.constraint_name = b.constraint_name;

MYSQL

select a.table_name,a.constraint_name,b.coulumn_name,a.constraint_type from information_schema.table_constraints a,information_schema.key_column_usage b where a.table_name = 'EMP' and a.table_schema= 'test' and a.table_name = b.table_name and a. table_schema = b.table_schema and a.constraint_name = b.constraint_name;

5.5 显示表结构

desc user;