MySQL的授权

grant 授权

什么是用户授权：在数据库服务器上添加新的连接用户，并设置权限和密码。

为什么要用授权：如果没有授权用户，那么只能有root用户在本机登陆数据库，其它用户无法登陆。
没有授权时，其它主机也无法访问数据库。

指令格式:

mysql> grant 权限列表 on 库名 to 用户名@"客户端地址" identified by "密码" ;

权限列表:

all 所有权限
usage 只能连接上数据库，没有任何权限
select,update,inseret ... 个别权限，这个权限对所有字段有效
select,update(字段1,字段2...) 只能对指定的字段有相应的权

库名:
*.* 所有库所有表
库名.* 一个库
库名.表名一张表

用户名:
授权时可以自定义,要有标识性,容易记,可以名中看出用途存储在mysql库的user表里

客户端地址:
% 表示互联网上的所有主机0
192.168.4.% 网段内的所有主机
192.168.4.1 1台主机
localhost 数据库服务器本机

授权举例1:
       添加admin用户,允许从192.168.4.0/24网段连接,对db3库的user表有查询权限,密码为123456
mysql> grant  select on db3.user to admin@"192.168.4.%" identified by "123456";


授权举例2:
      添加admin2,允许从本机连接,允许以db3库的所有表有 查询,更新,插入删除记录权限,密码为123456
mysql> grant select ,insert,update,delete on db3.* to admin2@"localhost" identified  by "123456";

授权库

grant授权的信息是保存在授权库中的，mysql库记录了授权信息，主要的表如下：
user 记录已有的授权用户及权限
db 记录已有授权用户对数据库的访问权限
tables_priv 记录已有授权用户对表的访问权限
columns_priv 记录已有授权用户对字段的访问权限

一 查看当前columns_priv，tables_priv,db,user表中的授权用户

mysql> select user,host,db,table_name,column_name from mysql.columns_priv;
Empty set (0.00 sec)                                #columns_priv表当前为空，说明当前数据库没有真对某些字段的授权  
   
mysql> select user,host,db,table_name from mysql.tables_priv;
+-----------+-----------+-----+------------+        #tables_priv表中只有系统默认的授权用户msyql.sys
| user      | host      | db  | table_name |
+-----------+-----------+-----+------------+
| mysql.sys | localhost | sys | sys_config |
+-----------+-----------+-----+------------+
mysql> select user,host,db from mysql.db;
+-----------+-----------+-----+                     #db表中也是系统默认授权用户mysql.sys
| user      | host      | db  |
+-----------+-----------+-----+
| mysql.sys | localhost | sys |
+-----------+-----------+-----+
mysql> select user,host  from mysql.user;
+-----------+-----------+                           #user表中有系统默认用户mysql.sys和root
| user      | host      |
+-----------+-----------+
| mysql.sys | localhost |
| root      | localhost |
+-----------+-----------+


二  添加真对school.student表中“学号”，“姓名”，“性别”这三个字段的授权用户col_user

mysql> grant select,update(学号,姓名,性别),insert on school.student to col_user@'%' identified by "123456";
mysql>  select user,host,db,table_name,column_name from mysql.columns_priv;
                                                   #在columns_priv表中查看授权用户,每条记录是一个授权字段
+----------+------+--------+------------+-------------+
| user     | host | db     | table_name | column_name |
+----------+------+--------+------------+-------------+
| col_user | %    | school | student    | 姓名        |
| col_user | %    | school | student    | 学号        |
| col_user | %    | school | student    | 性别        |
+----------+------+--------+------------+-------------+

mysql> select user,host,db,table_name from mysql.tables_priv;
+-----------+-----------+--------+------------+    #在tables_priv表中也可以看到该用户对school.student表有访问权限
| user      | host      | db     | table_name |    #具体权限需要用show grants查看
+-----------+-----------+--------+------------+
| col_user  | %         | school | student    |
| mysql.sys | localhost | sys    | sys_config |
+-----------+-----------+--------+------------+

mysql> show grants for col_user@'%'; #通过show grants查看col_user对school.student的具体权限
+-----------------------------------------------------------------------------------------------+
| Grants for col_user@% |
+-----------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'col_user'@'%' |
| GRANT SELECT, INSERT, UPDATE (性别, 学号, 姓名) ON `school`.`student` TO 'col_user'@'%' |
+-----------------------------------------------------------------------------------------------+

mysql> select user,host,db from mysql.db;
+-----------+-----------+-----+                     #db表中看不到该用户
| user      | host      | db  |
+-----------+-----------+-----+
| mysql.sys | localhost | sys |
+-----------+-----------+-----+

mysql> select user,host  from mysql.user;
+-----------+-----------+                           #在user表中可以看到该用户
| user      | host      |
+-----------+-----------+
| col_user  | %         |
| mysql.sys | localhost |
| root      | localhost |
+-----------+-----------+
mysql> 


三  添加授权用户tab_user1,tab_user2对表school.teacher，school.student的访问权限

mysql> grant all on school.teacher to tab_user1@'%' identified by "123456";
mysql> grant select on school.student to tab_user2@'%' identified by "123456";
mysql>  select user,host,db,table_name,column_name from mysql.columns_priv;
                                                    #colunm_priv表中授权记录的用户没有变化
+----------+------+--------+------------+-------------+
| user     | host | db     | table_name | column_name |
+----------+------+--------+------------+-------------+
| col_user | %    | school | student    | 姓名         |
| col_user | %    | school | student    | 学号         |
| col_user | %    | school | student    | 性别         |
+----------+------+--------+------------+-------------+
                                                    #tables_priv表中可以看到tab_user1,tab_user2用户
mysql> select user,host,db,table_name from mysql.tables_priv;
+-----------+-----------+--------+------------+
| user      | host      | db     | table_name |
+-----------+-----------+--------+------------+
| col_user  | %         | school | student    |
| tab_user1 | %         | school | teacher    |
| tab_user2 | %         | school | student    |
| mysql.sys | localhost | sys    | sys_config |
+-----------+-----------+--------+------------+
mysql> show grants for tab_user1@'%';              #通过show grants可以看出tab_user1,tab_user2的具体授权权限
+---------------------------------------------------------------+
| Grants for tab_user1@%                                        |
+---------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'tab_user1'@'%'                         |
| GRANT ALL PRIVILEGES ON `school`.`teacher` TO 'tab_user1'@'%' |
+---------------------------------------------------------------+
mysql> show grants for tab_user2@'%';
+-------------------------------------------------------+
| Grants for tab_user2@%                                |
+-------------------------------------------------------+
| GRANT USAGE ON *.* TO 'tab_user2'@'%'                 |
| GRANT SELECT ON `school`.`student` TO 'tab_user2'@'%' |
+-------------------------------------------------------+
                                                   
mysql> select user,host,db from mysql.db;           #db表中没有变化
+-----------+-----------+-----+
| user      | host      | db  |
+-----------+-----------+-----+
| mysql.sys | localhost | sys |
+-----------+-----------+-----+

mysql> select user,host  from mysql.user;           #user表中可以看到tab_user1,tab_user2
+-----------+-----------+
| user      | host      |
+-----------+-----------+
| col_user  | %         |
| tab_user1 | %         |
| tab_user2 | %         |
| mysql.sys | localhost |
| root      | localhost |
+-----------+-----------+
mysql> 


四 添加授权用户db_user1,db_user2用户对库school,school2的访问权限   
       
mysql> grant all on school.* to db_user1@'%' identified by "123456";
mysql> grant select on school2.* to db_user2@'%' identified by "123456";
mysql> select user,host,db,table_name,column_name from mysql.columns_priv;
                                                   #只要没有对任意表中字段的授权，column_priv表不会有变化
+----------+------+--------+------------+-------------+
| user     | host | db     | table_name | column_name |
+----------+------+--------+------------+-------------+
| col_user | %    | school | student    | 姓名        |
| col_user | %    | school | student    | 学号        |
| col_user | %    | school | student    | 性别        |
+----------+------+--------+------------+-------------+

mysql> select user,host,db,table_name from mysql.tables_priv;
                                                   #添加了真对库的授权用户，没有对表的授权用户所以db表中也不会变化
+-----------+-----------+--------+------------+
| user      | host      | db     | table_name |
+-----------+-----------+--------+------------+
| col_user  | %         | school | student    |
| tab_user1 | %         | school | teacher    |
| tab_user2 | %         | school | student    |
| mysql.sys | localhost | sys    | sys_config |
+-----------+-----------+--------+------------+

mysql> select user,host,db from mysql.db;         #db表中可以看到添加的授权用户
+-----------+-----------+---------+
| user      | host      | db      |
+-----------+-----------+---------+
| db_user1  | %         | school  |
| db_user2  | %         | school2 |
| mysql.sys | localhost | sys     |
+-----------+-----------+---------+

mysql> select user,host  from mysql.user;         #只要添加了授权用户user表中都会有记录
+-----------+-----------+
| user      | host      |
+-----------+-----------+
| col_user  | %         |
| db_user1  | %         |
| db_user2  | %         |
| tab_user1 | %         |
| tab_user2 | %         |
| mysql.sys | localhost |
| root      | localhost |
+-----------+-----------+
mysql> 



五  添加授权用户user对所有库和表有访问权限 

mysql> grant all on *.* to user@'%' identified by "123456";
mysql> select user,host,db,table_name,column_name from mysql.columns_priv;
+----------+------+--------+------------+-------------+
| user     | host | db     | table_name | column_name |
+----------+------+--------+------------+-------------+
| col_user | %    | school | student    | 姓名         |
| col_user | %    | school | student    | 学号         |
| col_user | %    | school | student    | 性别         |
+----------+------+--------+------------+-------------+
3 rows in set (0.00 sec)

mysql> select user,host,db,table_name from mysql.tables_priv;
+-----------+-----------+--------+------------+
| user      | host      | db     | table_name |
+-----------+-----------+--------+------------+
| col_user  | %         | school | student    |
| tab_user1 | %         | school | teacher    |
| tab_user2 | %         | school | student    |
| mysql.sys | localhost | sys    | sys_config |
+-----------+-----------+--------+------------+
4 rows in set (0.01 sec)

mysql> select user,host,db from mysql.db;
+-----------+-----------+---------+
| user      | host      | db      |
+-----------+-----------+---------+
| db_user1  | %         | school  |
| db_user2  | %         | school2 |
| mysql.sys | localhost | sys     |
+-----------+-----------+---------+
3 rows in set (0.00 sec)

mysql> select user,host  from mysql.user;        #只有在user表中可以看到use_user
+-----------+-----------+
| user      | host      |
+-----------+-----------+
| col_user  | %         |
| db_user1  | %         |
| db_user2  | %         |
| tab_user1 | %         |
| tab_user2 | %         |
| use_user  | %         |
| mysql.sys | localhost |
| root      | localhost |
+-----------+-----------+
mysql>

posted @ 2020-07-04 21:31 流浪剑客+ 阅读(820) 评论(0) 编辑收藏举报

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MySQL的授权

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