列权限管理 MySQL是由列级别权限存在的。这也体现了MySQL高级特性。实现了限制用户对表上特定列的访问权限。 一般都是实现对表级别不具备访问权限，但是对
列权限管理
MySQL是由列级别权限存在的。这也体现了MySQL高级特性。实现了限制用户对表上特定列的访问权限。 一般都是实现对表级别不具备访问权限，但是对某些列有访问权限。当然也存在其他情形。1# 列权限相关的字典表：
(root@localhost)[mysql]> desc columns_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 | | || Column_name | char(64) | NO | PRI | | || Timestamp | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP || Column_priv | set('Select','Insert','Update','References') | NO | | | |+-------------+----------------------------------------------+------+-----+-------------------+-----------------------------+7 rows in set (0.00 sec) 总共7列，很好理解。一条特定的列级别权限共需要定义5个维度，host+db+user+table+column。可授予的 权限种类分为4中，select, insert, update, refernces。其中前3项已经投入使用，references在5.6中还未正式 生效。2# 授权方法
列权限的授权方法和其他维度的授权方法有些许的差异，因为并非按照想像中会用on db.table.column这样的形式，而是将列名附带在授权种类之后：
测试update，确认没有update权限在name列上，表上也没有。
(test1@localhost)[sample2]> update smp set name='bbb';ERROR 1142 (42000): UPDATE command denied to user 'test1'@'localhost' for table 'smp'(test1@localhost)[sample2]> 对name列授权update：(root@localhost)[mysql]> grant update (name) on sample2.smp to test1;Query OK, 0 rows affected (0.00 sec) 再次尝试update name列，更新成功。(test1@localhost)[sample2]> update smp set name='bbb';Query OK, 1 row affected (0.00 sec)Rows matched: 1 Changed: 1 Warnings: 0 验证update id列，可以预见的失败：(test1@localhost)[sample2]> update smp set id=2;ERROR 1143 (42000): UPDATE command denied to user 'test1'@'localhost' for column 'id' in table 'smp'3# 权限的查询：
4个方式，一个是show grants，另一个是跑sql查询字典表,DBA可以查询mysql.columns_priv, 普通用户可以查询information_schema.COLUMN_PRIVILEGES。两者有细微的差别，但主要列一样,第四种方式是查询mysql.tables_priv。
#1，直接show grants(root@localhost)[mysql]> show grants for test1;+------------------------------------------------------------------------------------------------------+| Grants for test1@% |+------------------------------------------------------------------------------------------------------+| GRANT USAGE ON *.* TO 'test1'@'%' IDENTIFIED BY PASSWORD '*CFA887C680E792C2DCF622D56FB809E3F8BE63CC' || GRANT SELECT ON `sample2`.* TO 'test1'@'%' || GRANT ALL PRIVILEGES ON `sample`.* TO 'test1'@'%' WITH GRANT OPTION || GRANT SELECT ON `mysql`.`user` TO 'test1'@'%' || GRANT UPDATE (name) ON `sample2`.`smp` TO 'test1'@'%' || GRANT ALL PRIVILEGES ON `sample`.`smp` TO 'test1'@'%' |+------------------------------------------------------------------------------------------------------+6 rows in set (0.00 sec)#2，查询mysql.columns_priv;(root@localhost)[mysql]> select * from mysql.columns_priv;+------+---------+-------+------------+-------------+---------------------+-------------+| Host | Db | User | Table_name | Column_name | Timestamp | Column_priv |+------+---------+-------+------------+-------------+---------------------+-------------+| % | sample2 | test1 | smp | name | 0000-00-00 00:00:00 | Update |+------+---------+-------+------------+-------------+---------------------+-------------+1 row in set (0.00 sec)#3，查询information_schema.COLUMN_PRIVILEGES(root@localhost)[mysql]> select * from information_schema.COLUMN_PRIVILEGES;+-------------+---------------+--------------+------------+-------------+----------------+--------------+| GRANTEE | TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME | COLUMN_NAME | PRIVILEGE_TYPE | IS_GRANTABLE |+-------------+---------------+--------------+------------+-------------+----------------+--------------+| 'test1'@'%' | def | sample2 | smp | name | UPDATE | NO |+-------------+---------------+--------------+------------+-------------+----------------+--------------+1 row in set (0.00 sec)#4，查询mysql.tables_priv(root@localhost)[mysql]> select * from mysql.tables_priv where db='sample2';+------+---------+-------+------------+----------------+---------------------+------------+-------------+| Host | Db | User | Table_name | Grantor | Timestamp | Table_priv | Column_priv |+------+---------+-------+------------+----------------+---------------------+------------+-------------+| % | sample2 | test1 | smp | root@localhost | 0000-00-00 00:00:00 | | Update |+------+---------+-------+------------+----------------+---------------------+------------+-------------+1 row in set (0.00 sec)程序权限管理
MySQL的程序（process/routine） 一个全局权限：CREATE ROUTINE，在user,db表中体现 三个对象级权限，主要分为procedure和function两个对象类型。对于程序而言他们的权限种类有 1，EXECUTE #执行权限 2，ALTER ROUTINE #修改权限 3，GRANT #授予权限 相关的字典表：(root@localhost)[mysql]> desc procs_priv;+--------------+----------------------------------------+------+-----+-------------------+-----------------------------+| Field | Type | Null | Key | Default | Extra |+--------------+----------------------------------------+------+-----+-------------------+-----------------------------+| Host | char(60) | NO | PRI | | || Db | char(64) | NO | PRI | | || User | char(16) | NO | PRI | | || Routine_name | char(64) | NO | PRI | | || Routine_type | enum('FUNCTION','PROCEDURE') | NO | PRI | NULL | || Grantor | char(77) | NO | MUL | | || Proc_priv | set('Execute','Alter Routine','Grant') | NO | | | || Timestamp | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |+--------------+----------------------------------------+------+-----+-------------------+-----------------------------+8 rows in set (0.00 sec)