MySQL用户管理

1.用户

1.1 用户信息

mysql> use mysql;

Database changed

mysql> select host,user,authentication_string from user;

+-----------+---------------+-------------------------------------------+

| host       | user           | authentication_string |

+-----------+---------------+-------------------------------------------+

| localhost | root           | * 81 F5E21E35407D884A6CD4A731AEBFB6AF209E1B |

| localhost | mysq    l .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

 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 'wmh' @ '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 |

| wmh | localhost | * 84 AAC12F54AB666ECFC2A83C676908C8BBC381B1 | -- 新增用户

+---------------+-----------+-------------------------------------------+

4 rows in set ( 0.00 sec)

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 |

| wmh         | localhost | * 84 AAC12F54AB666ECFC2A83C676908C8BBC381B1 |

+---------------+-----------+-------------------------------------------+

4 rows in set ( 0.00 sec)

mysql> drop user wmh; -- 尝试删除

ERROR 1396 (HY000): Operation DROP USER failed for 'wmh' @ '%' -- <= 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 'wmh' @ '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)

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 | wmh          | * 84 AAC12F54AB666ECFC2A83C676908C8BBC381B1 |

+-----------+---------------+-------------------------------------------+

4 rows in set ( 0.00 sec)

mysql> set password for 'wmh' @ '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 | wmh         | * 5 D24C4D94238E65A6407DFAB95AA4EA97CA2B199 |

+-----------+---------------+-------------------------------------------+

4 rows in set ( 0.00 sec)

2.数据库的权限

MySQL数据库提供的权限列表：

 

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

*.* : 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

案例：

-- 使用 root 账号

-- 终端 A

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

| 57 test |

| bit_index |

| ccdata_pro |

| innodb_test |

| musicserver |

| myisam_test |

| mysql |

| order_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 wmh 赋予 test 数据库下所有文件的 select 权限

mysql> grant select on test.* to 'wmh' @ 'localhost' ;

Query OK, 0 rows affected ( 0.01 sec)

-- 使用 wmh 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 wmh 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 | blance |

+----+--------+---------+

| 2 | 李四 | 321.00 |

| 3 | 王五 | 5432.00 |

| 4 | 赵六 | 543.90 |

| 5 | 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 'wmh' @ 'localhost' for table

'account'

备注：特定用户现有查看权限

mysql> show grants for 'wmh' @ '%' ;

+-----------------------------------------------+

| Grants for wmh@% |

+-----------------------------------------------+

| GRANT USAGE ON *.* TO 'wmh' @ '%' |

| GRANT ALL PRIVILEGES ON `test`.* TO 'wmh' @ '%' |

+-----------------------------------------------+

2 rows in set ( 0.00 sec)

mysql> show grants for 'root' @ '%' ;

+-------------------------------------------------------------+

| Grants for root@% |

+-------------------------------------------------------------+

| GRANT ALL PRIVILEGES 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;  

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 wmh 对 test 数据库的所有权限

--root 身份，终端 A

mysql> revoke all on test.* from 'wmh' @ 'localhost' ;

Query OK, 0 rows affected ( 0.00 sec)

--wmh 身份，终端 B

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

| test |

+--------------------+

2 rows in set ( 0.00 sec)

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

+--------------------+

1 row in set ( 0.00 sec)