sql-statement-drop-role.md

title	summary
DROP ROLE	TiDB 数据库中 DROP ROLE 的使用概况。

DROP ROLE

使用 DROP ROLE 语句可删除已用 CREATE ROLE 语句创建的角色。

语法图

DropRoleStmt ::=
    'DROP' 'ROLE' ( 'IF' 'EXISTS' )? RolenameList

RolenameList ::=
    Rolename ( ',' Rolename )*

示例

创建新角色 analyticsteam 和新用户 jennifer：

$ mysql -uroot

CREATE ROLE analyticsteam;
Query OK, 0 rows affected (0.02 sec)

GRANT SELECT ON test.* TO analyticsteam;
Query OK, 0 rows affected (0.02 sec)

CREATE USER jennifer;
Query OK, 0 rows affected (0.01 sec)

GRANT analyticsteam TO jennifer;
Query OK, 0 rows affected (0.01 sec)

需要注意的是，默认情况下，用户 jennifer 需要执行 SET ROLE analyticsteam 语句才能使用与角色相关联的权限：

$ mysql -ujennifer

SHOW GRANTS;
+---------------------------------------------+
| Grants for User                             |
+---------------------------------------------+
| GRANT USAGE ON *.* TO 'jennifer'@'%'        |
| GRANT 'analyticsteam'@'%' TO 'jennifer'@'%' |
+---------------------------------------------+
2 rows in set (0.00 sec)

SHOW TABLES in test;
ERROR 1044 (42000): Access denied for user 'jennifer'@'%' to database 'test'
SET ROLE analyticsteam;
Query OK, 0 rows affected (0.00 sec)

SHOW GRANTS;
+---------------------------------------------+
| Grants for User                             |
+---------------------------------------------+
| GRANT USAGE ON *.* TO 'jennifer'@'%'        |
| GRANT Select ON test.* TO 'jennifer'@'%'    |
| GRANT 'analyticsteam'@'%' TO 'jennifer'@'%' |
+---------------------------------------------+
3 rows in set (0.00 sec)

SHOW TABLES IN test;
+----------------+
| Tables_in_test |
+----------------+
| t1             |
+----------------+
1 row in set (0.00 sec)

执行 SET DEFAULT ROLE 语句将用户 jennifer 与某一角色相关联，这样该用户无需执行 SET ROLE 语句就能拥有与角色相关联的权限。

$ mysql -uroot

SET DEFAULT ROLE analyticsteam TO jennifer;
Query OK, 0 rows affected (0.02 sec)

$ mysql -ujennifer

SHOW GRANTS;
+---------------------------------------------+
| Grants for User                             |
+---------------------------------------------+
| GRANT USAGE ON *.* TO 'jennifer'@'%'        |
| GRANT Select ON test.* TO 'jennifer'@'%'    |
| GRANT 'analyticsteam'@'%' TO 'jennifer'@'%' |
+---------------------------------------------+
3 rows in set (0.00 sec)

SHOW TABLES IN test;
+----------------+
| Tables_in_test |
+----------------+
| t1             |
+----------------+
1 row in set (0.00 sec)

删除角色 analyticsteam：

$ mysql -uroot

DROP ROLE analyticsteam;
Query OK, 0 rows affected (0.02 sec)

Jennifer 不再具有与 analyticsteam 关联的默认角色，或不能再将 analyticsteam 设为启用角色：

$ mysql -ujennifer

SHOW GRANTS;
+--------------------------------------+
| Grants for User                      |
+--------------------------------------+
| GRANT USAGE ON *.* TO 'jennifer'@'%' |
+--------------------------------------+
1 row in set (0.00 sec)

SET ROLE analyticsteam;
ERROR 3530 (HY000): `analyticsteam`@`%` is is not granted to jennifer@%

MySQL 兼容性

DROP ROLE 语句与 MySQL 8.0 的角色功能完全兼容。如发现任何兼容性差异，请在 GitHub 上提交 issue。

另请参阅

• CREATE ROLE
• GRANT <role>
• REVOKE <role>
• SET ROLE
• SET DEFAULT ROLE
• 基于角色的访问控制