## 模块 2: 授予权限

### 步骤 1. 连接到 TiDB

  ```bash
  mysql -h ${HOST_DB1_PRIVATE_IP} --port 4000 -u root
  ```

  ```sql
  USE test;
  ```

  ```output
  tidb> USE test;
  Database changed
  ```

### 步骤 2. 创建表 `emp`

  ```sql
  CREATE TABLE emp(id int, name varchar(20));
  ```

  ```output
  tidb> CREATE TABLE emp(id int, name varchar(20));
  Query OK, 0 rows affected (0.08 sec)
  ```

### 步骤 3. 向 `emp` 表插入一些数据

  ```sql
  INSERT INTO emp VALUES(1,'tom');
  ```

  ```output
  tidb> INSERT INTO emp VALUES(1,'tom');
  Query OK, 1 row affected (0.01 sec)
  ```

  ```sql
  INSERT INTO emp VALUES(2,'jack');
  ```

  ```output
  tidb> INSERT INTO emp VALUES(2,'jack');
  Query OK, 1 row affected (0.01 sec)
  ```

### 步骤 4. 创建用户 `jack`

+ 创建一个名为 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 且密码为 `pingcap` 的新用户。

  ```sql
  CREATE USER 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}' IDENTIFIED BY 'pingcap';
  ```

  ```output
  tidb> CREATE USER 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}' IDENTIFIED BY 'pingcap';
  Query OK, 0 rows affected (0.02 sec)
  ```

### 步骤 5. 创建两个角色 `r_mgr` 和 `r_emp`

  ```sql
  CREATE ROLE r_mgr, r_emp;
  ```

  ```output
  tidb> CREATE ROLE r_mgr, r_emp;
  Query OK, 0 rows affected (0.03 sec)
  ```

### 步骤 6. 向 `r_emp` 授予权限

+ 将 `test` 数据库中 `emp` 表的 `SELECT` 权限授予 `r_emp` 角色。

  ```sql
  GRANT SELECT ON test.emp TO r_emp;
  ```

  ```output
  tidb> GRANT SELECT ON test.emp TO r_emp;
  Query OK, 0 rows affected (0.02 sec)
  ```

### 步骤 7. 向 `r_mgr` 授予权限

+ 将 `test` 数据库中所有表的 `INSERT`, `UPDATE` 和 `DELETE` 权限授予 `r_mgr` 角色。

  ```sql
  GRANT INSERT, UPDATE, DELETE ON test.* TO r_mgr;
  ```

  ```output
  tidb> GRANT INSERT, UPDATE, DELETE ON test.* TO r_mgr;
  Query OK, 0 rows affected (0.02 sec)
  ```

### 步骤 8. 将 `r_emp` 角色授予 `r_mgr` 和 `jack`

+ 将 `r_emp` 角色授予 `r_mgr` 和 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}’`.

  ```sql
  GRANT r_emp TO r_mgr, 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}';
  ```

  ```output
  tidb> GRANT r_emp TO r_mgr, 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}';
  Query OK, 0 rows affected (0.03 sec)
  ```

### 步骤 9. 创建表 `dept` 并插入一些数据

  ```sql
  CREATE TABLE dept(id int, dname varchar(20));
  ```

  ```output
  tidb> CREATE TABLE dept(id int, dname varchar(20));
  Query OK, 0 rows affected (0.08 sec)
  ```

  ```sql
  INSERT INTO dept VALUES(1, 'dev');
  ```

  ```output
  tidb> INSERT INTO dept VALUES(1, 'dev');
  Query OK, 1 row affected (0.01 sec)
  ```

  ```sql
  INSERT INTO dept VALUES(2, 'sales');
  ```

  ```output
  tidb> INSERT INTO dept VALUES(2, 'sales');
  Query OK, 1 row affected (0.01 sec)
  ```

### 步骤 10. 向 `jack` 授予权限

+ 将 `test` 数据库中 `dept` 表的 `SELECT` 权限授予 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 用户。

  ```sql
  GRANT SELECT ON test.dept TO 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}';
  ```

  ```output
  tidb> GRANT SELECT ON test.dept TO 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}';
  Query OK, 0 rows affected (0.02 sec)
  ```

### 步骤 11. 启动一个新终端并登录到你的虚拟机

+ 我们将这个新终端称为[终端 2](ssh://monitor1-ssh#2) 。

### 步骤 12. 在终端2中，以 `jack` 身份连接到 `TiDB`

  ```bash
  mysql -h ${HOST_DB1_PRIVATE_IP} -P4000 -ujack -ppingcap
  ```

### 步骤 13. 在终端2中，从 `emp` 表和 `dept` 表检索数据

  ```sql
  USE test;
  ```

  ```output
  tidb> USE test;
  Database changed
  ```

  ```sql
  SELECT * FROM emp LIMIT 1;
  ```

  ```output
  tidb> SELECT * FROM emp LIMIT 1;
  ERROR 1142 (42000): SELECT command denied TO user 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}' for TABLE 'emp'
  ```

  ```sql
  SELECT * FROM dept LIMIT 1;
  ```

  ```output
  tidb> SELECT * FROM dept LIMIT 1;
  +------+-------+
  | id   | dname |
  +------+-------+
  |    1 | dev   |
  +------+-------+
  1 row in set (0.00 sec)
  ```

+ 用户 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 没有从 `emp` 表检索行的权限。该权限是通过 `r_emp` 角色授予的，但在这个会话中未启用该角色。

+ 用户 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 有权从 `dept` 表检索行。该权限是直接授予该用户的。

### 步骤 14. 查看 `jack` 的角色

+ 查看 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 在会话中激活了哪些角色，并显示授予该用户的所有权限。

  ```sql
  SELECT CURRENT_ROLE();
  ```

  ```output
  tidb> SELECT CURRENT_ROLE();
  +----------------+
  | CURRENT_ROLE() |
  +----------------+
  | NONE           |
  +----------------+
  1 row in set (0.00 sec)
  ```

  ```sql
  SHOW GRANTS;
  ```

  ```output
  tidb> SHOW GRANTS;
  +----------------------------------------------------+
  | GRANT USAGE ON *.* TO 'jack'@'172.31.0.106'        |
  | GRANT SELECT ON test.dept TO 'jack'@'172.31.0.106' |
  | GRANT 'r_emp'@'%' TO 'jack'@'172.31.0.106'         |
  +----------------------------------------------------+
  3 rows in set (0.00 sec)
  ```

  + 该会话没有启用任何角色。

  + 用户已被授予 `r_emp` 角色，但尚未激活。

### 在 15. 激活授予 `jack` 的所有角色

+ 在已连接的会话中激活授予用户 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 的所有角色，并查看已启用了哪些角色。然后，再次显示授予该用户的所有权限。

  ```sql
  SET ROLE ALL;
  ```

  ```output
  tidb> SET ROLE ALL;
  Query OK, 0 rows affected (0.00 sec)
  ```

  ```sql
  SELECT CURRENT_ROLE();
  ```

  ```output
  tidb> SELECT CURRENT_ROLE();
  +----------------+
  | CURRENT_ROLE() |
  +----------------+
  | `r_emp`@`%`    |
  +----------------+
  1 row in set (0.01 sec)
  ```

  ```sql
  SHOW GRANTs;
  ```

  ```output
  tidb> SHOW GRANTS;
  +----------------------------------------------------+
  | GRANT USAGE ON *.* TO 'jack'@'172.31.0.106'        |
  | GRANT SELECT ON test.dept TO 'jack'@'172.31.0.106' |
  | GRANT SELECT ON test.emp TO 'jack'@'172.31.0.106'  |
  | GRANT 'r_emp'@'%' TO 'jack'@'172.31.0.106'         |
  +----------------------------------------------------+
  4 rows in set (0.00 sec)
  ```

+ 在会话中激活一个角色后，`SHOW GRANTS` 的结果将包含授予该角色的所有权限。

### 步骤 16. 在终端2中，尝试从 `emp` 表检索1行数据

  ```sql
  SELECT * FROM emp LIMIT 1;
  ```

  ```output
  tidb> SELECT * FROM emp LIMIT 1;
  +------+------+
  | id   | name |
  +------+------+
  |    1 | tom  |
  +------+------+
  1 row in set (0.01 sec)
  ```

+ 用户 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 在启用 `r_emp` 角色后有权从`emp`表检索行

### 步骤 17. 在终端2中，从 `emp` 表删除数据

+ 在[终端 2](ssh://monitor1-ssh#2)中，尝试从 `emp` 表删除 `id`=1 的 `emp`

  ```sql
  DELETE FROM emp WHERE id=1;
  ```

  ```output
  tidb> DELETE FROM emp WHERE id=1;
  DELETE command denied to user 'jack'@'172.31.0.106' for table 'emp'
  ```

  + 用户 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 没有从员工表中删除行的权限。