13.用户管理
13.1用户
13.1.1用户信息
MySQL 中的用户，都存储在系统数据库 mysql 的 user 表中。
mysql> use mysql;
Database changed
mysql> select host,user,authentication_string from user;
+-----------+---------------+-------------------------------------------+
| host | user | authentication_string |
+-----------+---------------+-------------------------------------------+
| localhost | root | *81F5E21E35407D884A6CD4A731AEBF6AF209E1B |
| localhost | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
+-----------+---------------+-------------------------------------------+
- 可以通过
desc user初步查看一下表结构
字段解释：
host：表示这个用户可以从哪个主机登陆，如果是 localhost，表示只能从本机登陆。user：用户名。authentication_string：用户密码通过password函数加密后的。*\ _ priv：用户拥有的权限。
13.1.2 创建用户
语法：
create user '用户名'@'登陆主机/ip' identified by '密码';
案例：
mysql> create user 'xixi'@'localhost' identified by '12345678';
Query OK, 0 rows affected (0.06 sec)
mysql> select user,host,authentication_string from user;
+---------------+-----------+-------------------------------------------+
| user | host | authentication_string |
+---------------+-----------+-------------------------------------------+
| root | % | *A2F7C9D334175DE9AF4DB4F5473E0BD0F5FA9E75 |
| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| whb | localhost | *84AAC12F54AB666ECFC2A83C676908C8BBC381B1 | -- 新增用户
+---------------+-----------+-------------------------------------------+
4 rows in set (0.00 sec)
-- 此时便可以使用新账号新密码进行登陆啦
备注：
- 可能实际在设置密码的时候，因为 mysql 本身的认证等级比较高，一些简单的密码无法设置，会爆出如下报错：
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
解决方案：
关于新增用户这里，需要大家注意，不要轻易添加一个可以从任意地方登陆的 user。
13.1.3 删除用户
语法：
drop user '用户名'@'主机名'
示例：
mysql> select user,host,authentication_string from user;
+---------------+-----------+-------------------------------------------+
| user | host | authentication_string |
+---------------+-----------+-------------------------------------------+
| root | % | *A2F7C9D334175DE9AF4DB4F5473E0BD0F5FA9E75 |
| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| xixi | localhost | *84AAC12F54AB666ECFC2A83C676908C8BBC381B1 |
+---------------+-----------+-------------------------------------------+
4 rows in set (0.00 sec)
mysql> drop user xixi; -- 尝试删除
ERROR 1396 (HY000): Operation DROP USER failed for 'whb'@'%' -- <= 直接给个用户名，不能删除，它默认是%，表示所有地方可以登陆的用户
mysql> drop user 'xixi'@'localhost'; -- 删除用户
Query OK, 0 rows affected (0.00 sec)
mysql> select user,host,authentication_string from user;
+---------------+-----------+-------------------------------------------+
| user | host | authentication_string |
+---------------+-----------+-------------------------------------------+
| root | % | *A2F7C9D334175DE9AF4DB4F5473E0BD0F5FA9E75 |
| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
+---------------+-----------+-------------------------------------------+
3 rows in set (0.00 sec)
13.1.4 修改用户密码
语法：
- 自己改自己密码
set password=password('新的密码');
- root 用户修改指定用户的密码
set password for '用户名'@'主机名'=password('新的密码');
mysql> select host,user, authentication_string from user;
+-----------+---------------+-------------------------------------------+
| host | user | authentication_string |
+-----------+---------------+-------------------------------------------+
| % | root | *A2F7C9D334175DE9AF4DB4F5473E0BD0F5FA9E75 |
| localhost | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | xixi | *84AAC12F54AB666ECFC2A83C676908C8BBC381B1 |
+-----------+---------------+-------------------------------------------+
4 rows in set (0.00 sec)
mysql> set password for 'xixi'@'localhost'=password('87654321');
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> select host,user, authentication_string from user;
+-----------+---------------+-------------------------------------------+
| host | user | authentication_string |
+-----------+---------------+-------------------------------------------+
| % | root | *A2F7C9D334175DE9AF4DB4F5473E0BD0F5FA9E75 |
| localhost | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | xixi | *5D24C4D94238E65A6407DFAB95AA4AE97CA2B199 |
+-----------+---------------+-------------------------------------------+
4 rows in set (0.00 sec)
13.2 数据库的权限
MySQL 数据库提供的权限列表：
| 权限 | 列 | 上下文 |
|---|---|---|
| CREATE | Create_priv | 数据库、表或索引 |
| DROP | Drop_priv | 数据库或表 |
| GRANT OPTION | Grant_priv | 数据库、表或保存的程序 |
| REFERENCES | References_priv | 数据库或表 |
| ALTER | Alter_priv | 表 |
| DELETE | Delete_priv | 表 |
| INDEX | Index_priv | 表 |
| INSERT | Insert_priv | 表 |
| UPDATE | Update_priv | 表 |
| CREATE VIEW | Create_view_priv | 视图 |
| SHOW VIEW | Show_view_priv | 视图 |
| ALTER ROUTINE | Alter_routine_priv | 保存的程序 |
| CREATE ROUTINE | Create_routine_priv | 保存的程序 |
| EXECUTE | Execute_priv | 保存的程序 |
| FILE | File_priv | 服务器主机上的文件访问 |
| CREATE TEMPORARY TABLES | Create_tmp_table_priv | 服务器管理 |
| LOCK TABLES | Lock_tables_priv | 服务器管理 |
| CREATE USER | Create_user_priv | 服务器管理 |
| PROCESS | Process_priv | 服务器管理 |
| RELOAD | Reload_priv | 服务器管理 |
| REPLICATION CLIENT | Repl_client_priv | 服务器管理 |
| REPLICATION SLAVE | Repl_slave_priv | 服务器管理 |
| SHOW DATABASES | Show_db_priv | 服务器管理 |
| SHUTDOWN | Shutdown_priv | 服务器管理 |
| SUPER | Super_priv | 服务器管理 |
13.2.1 给用户授权
刚创建的用户没有任何权限，需要给用户授权。
- 语法：
grant 权限列表 on 库.对象名 to '用户名'@'登陆位置' [identified by '密码']
- 说明：
- 权限列表，多个权限用逗号分开
grant select on ...grant select, delete, create on ...grant all [privileges] on ...– 表示赋予该用户在该对象上的所有权限
*.*：代表本系统中的所有数据库的所有对象（表，视图，存储过程等）库.*：表示某个数据库中的所有数据对象（表，视图，存储过程等）identified by可选。如果用户存在，赋予权限的同时修改密码；如果该用户不存在，就是创建用户
- 权限列表，多个权限用逗号分开
- 案例：
-- 使用root账号
-- 终端A
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| 57test |
| bit_index |
| ccdata_pro |
| innodbserver |
| myisam_test |
| mysql |
| mysql_sys |
| performance_schema |
| scott |
| sys |
| test |
| vod_system |
+--------------------+
14 rows in set (0.00 sec)
mysql> use test;
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| account |
| student |
| user |
+----------------+
3 rows in set (0.01 sec)
-- 给用户whb赋予test数据库下所有文件的select权限
mysql> grant select on test.* to 'whb'@'localhost';
Query OK, 0 rows affected (0.01 sec)
-- 使用whb账号
-- 终端B
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
+--------------------+
1 row in set (0.00 sec)
-- 暂停等root用户给whb赋完权之后，在查看
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| test | -- 赋完权之后，就能看到新的表
+--------------------+
2 rows in set (0.01 sec)
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| account |
| student |
| user |
+----------------+
3 rows in set (0.00 sec)
mysql> select * from account;
+----+-------+---------+
| id | name | balance |
+----+-------+---------+
| 2 | 李四 | 321.00 |
| 3 | 王五 | 543.00 |
| 4 | 赵六 | 543.90 |
+----+-------+---------+
4 rows in set (0.00 sec)
-- 没有删除权限
mysql> delete from account;
ERROR 1142 (42000): DELETE command denied to user 'whb'@'localhost' for table 'account'
备注: 特定用户现有查看权限
mysql> show grants for 'whb'@'%';
+-----------------------------------------------------+
| Grants for whb@% |
+-----------------------------------------------------+
| GRANT USAGE ON *.* TO 'whb'@'%' |
| GRANT ALL PRIVILEGES ON `whb`.* TO 'whb'@'%' |
+-----------------------------------------------------+
2 rows in set (0.00 sec)
mysql> show grants for 'root'@'%';
+---------------------------------------------------------------------+
| Grants for root@% |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'%' WITH GRANT OPTION |
+---------------------------------------------------------------------+
1 row in set (0.00 sec)
注意: 如果发现赋权限后，没有生效，执行如下指令:
flush privileges;
13.2.2 回收权限
- 语法：
revoke 权限列表 on 库.对象名 from '用户名'@'登陆位置';
- 示例：
-- 回收whb对test数据库的所有权限
-- root身份，终端A
mysql> revoke all on test.* from 'whb'@'localhost';
Query OK, 0 rows affected (0.00 sec)
-- whb身份，终端B
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
+--------------------+
2 rows in set (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
+--------------------+
1 row in set (0.00 sec)