mysql.db数据库层权限该如何设置

本文主要给大家简单讲讲mysql.db数据库层权限该如何设置，相关专业术语大家可以上网查查或者找一些相关书籍补充一下，这里就不涉猎了，我们就直奔主题吧，希望mysql.db数据库层权限该如何设置这篇文章可以给大家带来一些实际帮助。

1# 数据库层权限记录位置
表级别的权限记录在mysql.tables_priv表中。

(root@localhost)[mysql]> (root@localhost)[mysql]> desc tables_priv;+-------------+-----------------------------------------------------------------------------------------------------------------------------------+------+-----+-------------------+-----------------------------+| Field       | Type                                                                                                                              | Null | Key | Default           | Extra                       |+-------------+-----------------------------------------------------------------------------------------------------------------------------------+------+-----+-------------------+-----------------------------+| Host        | char(60)                                                                                                                          | NO   | PRI |                   |                             || Db          | char(64)                                                                                                                          | NO   | PRI |                   |                             || User        | char(16)                                                                                                                          | NO   | PRI |                   |                             || Table_name  | char(64)                                                                                                                          | NO   | PRI |                   |                             || Grantor     | char(77)                                                                                                                          | NO   | MUL |                   |                             || Timestamp   | timestamp                                                                                                                         | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP || Table_priv  | set('Select','Insert','Update','Delete','Create','Drop','Grant','References','Index','Alter','Create View','Show view','Trigger') | NO   |     |                   |                             || Column_priv | set('Select','Insert','Update','References')                                                                                      | NO   |     |                   |                             |+-------------+-----------------------------------------------------------------------------------------------------------------------------------+------+-----+-------------------+-----------------------------+8 rows in set (0.00 sec)

然而关于数据库层面的权限记录在mysql.db表中

(root@localhost)[mysql]> desc db;+-----------------------+---------------+------+-----+---------+-------+| Field                 | Type          | Null | Key | Default | Extra |+-----------------------+---------------+------+-----+---------+-------+| Host                  | char(60)      | NO   | PRI |         |       || Db                    | char(64)      | NO   | PRI |         |       || User                  | char(16)      | NO   | PRI |         |       || Select_priv           | enum('N','Y') | NO   |     | N       |       || Insert_priv           | enum('N','Y') | NO   |     | N       |       || Update_priv           | enum('N','Y') | NO   |     | N       |       || Delete_priv           | enum('N','Y') | NO   |     | N       |       || Create_priv           | enum('N','Y') | NO   |     | N       |       || Drop_priv             | enum('N','Y') | NO   |     | N       |       || Grant_priv            | enum('N','Y') | NO   |     | N       |       || References_priv       | enum('N','Y') | NO   |     | N       |       || Index_priv            | enum('N','Y') | NO   |     | N       |       || Alter_priv            | enum('N','Y') | NO   |     | N       |       || Create_tmp_table_priv | enum('N','Y') | NO   |     | N       |       || Lock_tables_priv      | enum('N','Y') | NO   |     | N       |       || Create_view_priv      | enum('N','Y') | NO   |     | N       |       || Show_view_priv        | enum('N','Y') | NO   |     | N       |       || Create_routine_priv   | enum('N','Y') | NO   |     | N       |       || Alter_routine_priv    | enum('N','Y') | NO   |     | N       |       || Execute_priv          | enum('N','Y') | NO   |     | N       |       || Event_priv            | enum('N','Y') | NO   |     | N       |       || Trigger_priv          | enum('N','Y') | NO   |     | N       |       |+-----------------------+---------------+------+-----+---------+-------+22 rows in set (0.00 sec)(root@localhost)[mysql]> select * from db\G*************************** 1. row ***************************                 Host: %                   Db: sample                 User: test1          Select_priv: Y          Insert_priv: N          Update_priv: N          Delete_priv: N          Create_priv: Y            Drop_priv: N           Grant_priv: N      References_priv: N           Index_priv: N           Alter_priv: NCreate_tmp_table_priv: N     Lock_tables_priv: N     Create_view_priv: N       Show_view_priv: N  Create_routine_priv: N   Alter_routine_priv: N         Execute_priv: N           Event_priv: N         Trigger_priv: N1 row in set (0.00 sec)

这条对应的grant语句是：

(root@localhost)[mysql]> show grants for test1;+------------------------------------------------------------------------------------------------------+| Grants for test1@%                                                                                   |+------------------------------------------------------------------------------------------------------+| GRANT USAGE ON *.* TO 'test1'@'%' IDENTIFIED BY PASSWORD '*CFA887C680E792C2DCF622D56FB809E3F8BE63CC' || GRANT SELECT, CREATE ON `sample`.* TO 'test1'@'%'                                                    || GRANT ALL PRIVILEGES ON `sample`.`smp` TO 'test1'@'%'                                                || GRANT SELECT ON `mysql`.`user` TO 'test1'@'%'                                                        |+------------------------------------------------------------------------------------------------------+4 rows in set (0.00 sec)

第二条：
GRANT SELECT, CREATE ON sample.* TO 'test1'@'%'

尝试再增加权限：

(root@localhost)[mysql]> grant all privileges on sample.* to test1;Query OK, 0 rows affected (0.00 sec)(root@localhost)[mysql]> (root@localhost)[mysql]> (root@localhost)[mysql]> select * from db\G*************************** 1. row ***************************                 Host: %                   Db: sample                 User: test1          Select_priv: Y          Insert_priv: Y          Update_priv: Y          Delete_priv: Y          Create_priv: Y            Drop_priv: Y           Grant_priv: N      References_priv: Y           Index_priv: Y           Alter_priv: YCreate_tmp_table_priv: Y     Lock_tables_priv: Y     Create_view_priv: Y       Show_view_priv: Y  Create_routine_priv: Y   Alter_routine_priv: Y         Execute_priv: Y           Event_priv: Y         Trigger_priv: Y1 row in set (0.00 sec)

授予all privileges权限。注意点是grant option并不包含在all privileges里面。可以用with子句

(root@localhost)[mysql]> grant all privileges on sample.* to test1 with grant option;Query OK, 0 rows affected (0.00 sec)(root@localhost)[mysql]> select * from db\G*************************** 1. row ***************************                 Host: %                   Db: sample                 User: test1          Select_priv: Y          Insert_priv: Y          Update_priv: Y          Delete_priv: Y          Create_priv: Y            Drop_priv: Y           Grant_priv: Y      References_priv: Y           Index_priv: Y           Alter_priv: YCreate_tmp_table_priv: Y     Lock_tables_priv: Y     Create_view_priv: Y       Show_view_priv: Y  Create_routine_priv: Y   Alter_routine_priv: Y         Execute_priv: Y           Event_priv: Y         Trigger_priv: Y1 row in set (0.00 sec)

回收all privileges权限, 错误写法，revoke并不能带with grant option来回收grant option

(root@localhost)[mysql]> revoke all privileges on sample.* from test1 with grant option;ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'grant option' at line 1(root@localhost)[mysql]> 

这样写还是不对：

revoke all privileges, grant option  on sample.* from test1;ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'on sample.* from test1' at line 1

分开写就可以了：

(root@localhost)[mysql]> revoke all privileges on sample.* from test1;Query OK, 0 rows affected (0.00 sec)(root@localhost)[mysql]> revoke grant option on sample.* from test1;Query OK, 0 rows affected (0.00 sec)(root@localhost)[mysql]> 

grant option在授予的时候是用with子句，回收的时候需要单独回收。

2#一般用户可访问的数据库：
在test1用户下，查看可以访问的数据库：

(test1@localhost)[(none)]> show databases    -> ;+--------------------+| Database           |+--------------------+| information_schema || mysql              || sample             |+--------------------+3 rows in set (0.00 sec)(test1@localhost)[(none)]> (test1@localhost)[(none)]> (test1@localhost)[(none)]> (test1@localhost)[(none)]> use mysql;Reading table information for completion of table and column namesYou can turn off this feature to get a quicker startup with -ADatabase changed(test1@localhost)[mysql]> show tables;+-----------------+| Tables_in_mysql |+-----------------+| user            |                #由于只有user表上被授予了select权限，所以show tables只能看到一个表+-----------------+1 row in set (0.00 sec)(test1@localhost)[mysql]> show grants;+---------------------------------------------------------------------+| Grants for test1@%                                                  |+---------------------------------------------------------------------+| GRANT USAGE ON *.* TO 'test1'@'%' IDENTIFIED BY PASSWORD    || GRANT ALL PRIVILEGES ON `sample`.* TO 'test1'@'%' WITH GRANT OPTION || GRANT ALL PRIVILEGES ON `sample`.`smp` TO 'test1'@'%'               || GRANT SELECT ON `mysql`.`user` TO 'test1'@'%'                       |+---------------------------------------------------------------------+4 rows in set (0.00 sec)-----------------------------------------------------------------+| Grants for test1@%                                                |+-------------------------------------------------------------------+| GRANT USAGE ON *.* TO 'test1'@'%' IDENTIFIED BY PASSWORD  || GRANT ALL PRIVILEGES ON `sample`.`smp` TO 'test1'@'%'             || GRANT SELECT ON `mysql`.`user` TO 'test1'@'%'                     |+-------------------------------------------------------------------+3 rows in set (0.00 sec)(test1@localhost)[mysql]> 

sample数据库是被授予的all privileges,所以全库的表对象都是可用呗test1用户访问。至于mysql，只有user表上有一个select权限，所以也被归类在可用访问的数据库之列，但是实际上用show tables只能看到一个表。

3# 数据库层权限的从无到有，给一个用户授予权限后，db表的变化：
a# 建立一个新的数据库sample2

(root@localhost)[(none)]> create database sample2;Query OK, 1 row affected (0.00 sec)

这个时候查看用户test1所拥有的数据库权限，是只有sample数据库。MYSQL数据库并不显示。

(root@localhost)[mysql]> select * from db\G*************************** 1. row ***************************                 Host: %                   Db: sample                 User: test1          Select_priv: Y          Insert_priv: Y          Update_priv: Y          Delete_priv: Y          Create_priv: Y            Drop_priv: Y           Grant_priv: Y      References_priv: Y           Index_priv: Y           Alter_priv: YCreate_tmp_table_priv: Y     Lock_tables_priv: Y     Create_view_priv: Y       Show_view_priv: Y  Create_routine_priv: Y   Alter_routine_priv: Y         Execute_priv: Y           Event_priv: Y         Trigger_priv: Y1 row in set (0.00 sec)(root@localhost)[mysql]>#这个时候test1用户去尝试访问sample2数据库也是失败的：(test1@localhost)[sample]> use sample2ERROR 1044 (42000): Access denied for user 'test1'@'%' to database 'sample2'(test1@localhost)[sample]>

运行授权语句，对test1受援sample2的select权限，这个时候mysql.db数据库中出现了2行数据，多了一行关于sample2的记录：

(root@localhost)[mysql]> select * from db\G*************************** 1. row ***************************                 Host: %                   Db: sample2                 User: test1          Select_priv: Y          Insert_priv: N          Update_priv: N          Delete_priv: N          Create_priv: N            Drop_priv: N           Grant_priv: N      References_priv: N           Index_priv: N           Alter_priv: NCreate_tmp_table_priv: N     Lock_tables_priv: N     Create_view_priv: N       Show_view_priv: N  Create_routine_priv: N   Alter_routine_priv: N         Execute_priv: N           Event_priv: N         Trigger_priv: N*************************** 2. row ***************************                 Host: %                   Db: sample                 User: test1          Select_priv: Y          Insert_priv: Y          Update_priv: Y          Delete_priv: Y          Create_priv: Y            Drop_priv: Y           Grant_priv: Y      References_priv: Y           Index_priv: Y           Alter_priv: YCreate_tmp_table_priv: Y     Lock_tables_priv: Y     Create_view_priv: Y       Show_view_priv: Y  Create_routine_priv: Y   Alter_routine_priv: Y         Execute_priv: Y           Event_priv: Y         Trigger_priv: Y2 rows in set (0.00 sec)

从记录可用看到test1用户对sample2数据库拥有select权限。也就是访问权限，表示里面的对象都具有。但是里面是没有表的。

(test1@localhost)[(none)]> use sample2;Database changed(test1@localhost)[sample2]> show tables;Empty set (0.00 sec)

#并且test1用户可用select出smp表的数据。(test1@localhost)[sample2]> select * from smp;+------+------+| id   | name |+------+------+|    1 | aaa  |+------+------+1 row in set (0.00 sec)# 然而test1用户并不显示的拥有任在sample2上的表权限。所谓的权限的继承。(test1@localhost)[information_schema]> select * from TABLE_PRIVILEGES where TABLE_SCHEMA='sample2';Empty set (0.00 sec)

#奇怪，并没有给表smp授权select，受援的是select on sample2.*。尝试单独对表收回select 权限：

(root@localhost)[sample2]> revoke select on sample2.smp from test1;ERROR 1147 (42000): There is no such grant defined for user 'test1' on host '%' on table 'smp'#以失败告终。显示的revoke并不能收回隐式继承来的权限。(test1@localhost)[sample2]> show tables;+-------------------+| Tables_in_sample2 |+-------------------+| smp               |+-------------------+1 row in set (0.00 sec)

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