MySQL用户管理

Posted 2020-11-15 wangziqiang123

用户管理

1、新建普通用户

（1）使用CREATE USER语句创建新用户

使用格式：

CREATE USER  'user'@'host' [IDENTIFIED BY [PASSWORD] 'password'] [,'user'@'host' [IDENTIFIED BY [PASSWORD] 'password']...]

    user：新建用户
    host：主机名
    IDENTIFIED BY 设置用户密码

示例：

MariaDB [(none)]> CREATE USER test@'localhost' IDENTIFIED BY '123456';

在mysql.user表中会插入一行记录

MariaDB [(none)]> SELECT user,host,password FROM mysql.user;
+------+-----------------------+-------------------------------------------+
| user | host                  | password                                  |
+------+-----------------------+-------------------------------------------+
| root | localhost             |                                           |
| root | localhost.localdomain |                                           |
| root | 127.0.0.1             |                                           |
| root | ::1                   |                                           |
|      | localhost             |                                           |
|      | localhost.localdomain |                                           |
| test | localhost             | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
+------+-----------------------+-------------------------------------------+

（2）在musql.user表中INSERT用户

MariaDB [(none)]> INSERT INTO mysql.user (user,host,password) VALUES ("testA","192.168.4.60",PASSWORD('123456'));

执行完INSERT之后，要使用如下命令生效。
MariaDB [(none)]> FLUSH PRIVILEGES;

（3）使用GRANT创建用户

使用格式：

GRANT priv_type ON database.table TO user[IDENTIFIED BY [PASSWORD] 'password'] [,user [IDENTIFIED BY [PASSWORD] 'password']...]

    priv_type：授予的权限
    database.table：权限的范围
    user：新建用户
    IDENTIFIED BY 设置密码

示例：

MariaDB [(none)]> GRANT SELECT ON *.* TO testB@'192.168.4.60' IDENTIFIED BY '123456';

2、重命名

使用格式：

RENAME USER old_user TO new_user[, old_user TO new_user] ...

示例：

MariaDB [(none)]> RENAME USER testA@'192.168.4.60' TO testC@'192.168.4.60';

3、删除用户

使用格式：

DROP USER 'user'@'host' [, 'user'@'host'] ...

示例：

MariaDB [class]> DROP USER testC@'192.168.4.60';

4、修改用户密码

（1）使用mysqladmin命令修改密码

使用格式：

mysqladmin -uUSERNAME -hHOST -p  password 'NEW_PASS'

示例：

[root@localhost~]#mysqladmin -uroot -p password

Enter password: 
New password: 
Confirm new password: 

[root@localhost~]#mysqladmin -utest -p password 'testabd'

Enter password: 
mysqladmin: Can't turn off logging; error: 'Access denied; you need (at least one of) the SUPER privilege(s) for this operation'

修改普通用户需要超级管理权限

（2）修改mysql.user表

使用格式：

UPDATE mysql.user SET Password=PASSWORD('cleartext password')  WHERE User='USERNAME' AND Host='HOST';

示例：

MariaDB [(none)]> UPDATE mysql.user SET PASSWORD=PASSWORD('testabcd') WHERE User='test';

（3）使用SET语句修改密码

使用格式：

SET PASSWORD [FOR 'user'@'host'] = PASSWORD('cleartext password');

示例：

MariaDB [(none)]> SET PASSWORD FOR test@'localhost'=PASSWORD('testabcd');

（4）GRANT语句修改普通用户密码

示例：

MariaDB [(none)]> GRANT SELECT ON *.* TO 'test'@'localhost' IDENTIFIED BY '123456';

5、忘记管理员密码如何解决？

（1）先确保mysql服务停止

[root@localhost~]#systemctl stop mariadb.service

（2）确保其他用户连接不到mysql服务

（3）修改启动配置文件

[root@localhost~]#vim /usr/lib/systemd/system/mariadb.service

（4）启动服务并修改密码

[root@localhost~]#systemctl restart mariadb.service

MariaDB [(none)]> UPDATE mysql.user SET PASSWORD=PASSWORD('123456') WHERE user='root';

（5）修改更改文件

[root@localhost~]#systemctl stop mariadb.service

[root@localhost~]#vim /usr/lib/systemd/system/mariadb.service 删除刚添加的参数

（6）重启服务测试

[root@localhost~]#systemctl restart mariadb.service

[root@localhost~]#mysql -uroot -p

Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or g.
Your MariaDB connection id is 3
Server version: 5.5.56-MariaDB MariaDB Server

授权

使用格式：

GRANT  priv_type [(column_list)] [, priv_type [(column_list)]] ...
            ON [object_type] priv_level
            TO user_specification [, user_specification] ...
            [REQUIRE {NONE | ssl_option [[AND] ssl_option] ...}]
            [WITH with_option ...]

    priv_type：表示权限类型
    column_list：设置列
    user：设置用户
    password：用户密码

    WITH关键字后面带有一个或多个with_option参数

        GRANT OPTION：被授权用户可以使用的参数

            MAX_QUERIES_PER_HOUR count：设置每小时允许执行的count查询
            MAX_UPDATES_PER_HOUR count：设置每小时count更新
            MAX_CONNECTIONS_PER_HOUR count：设置每小时可以建立count连接
            MAX_USER_CONNECTIONS count：设置单个用户可以同时具有count连接数

示例：

MariaDB [class]> GRANT SELECT(number) ON class.class TO 'test'@'localhost' IDENTIFIED BY '123456';

查看授权

使用格式：

SHOW GRANTS [FOR 'user'@'host']

示例：

MariaDB [class]> SHOW GRANTS FOR test@'localhost'G;

*************************** 1. row ***************************
Grants for test@localhost: GRANT SELECT ON *.* TO 'test'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9'
*************************** 2. row ***************************
Grants for test@localhost: GRANT SELECT (number) ON `class`.`class` TO 'test'@'localhost'


MariaDB [class]> SHOW GRANTS ;  #默认查询root的权限

取消授权

使用格式

REVOKE  priv_type [(column_list)][, priv_type [(column_list)]] ...
            ON [object_type] priv_level
            FROM  'user'@'host' [,  'user'@'host'] ...

示例：

MariaDB [class]> REVOKE SELECT(number) ON class.class FROM test@'localhost';

原文:大专栏  MySQL用户管理