用户管理
Mysql的用户管理包括两个部分，用户名和机器名，只要其中的一个不同，那么就是不同的用户。
一，mysql的权限类型
管理权限
数据库的访问权限
二，一些特殊权限
ALl和All PRIVILEGE表示的是全部权限，但是不能将权限授予其他的用户
USAGE 表示的是没有权限，不能访问数据库的任何数据，但是可以连接到数据库。还有就是可以查看系统变量。show variables 和show status
三，权限级别
四，关于授权的表
mysql用户管理
一，创建和删除用户
mysql> select current_user(); 查询当前的登录用户
+----------------+
| current_user() |
+----------------+
| root@localhost |
+----------------+
创建用户的时候没有分配任何权限，%表示的是任何机器，但是不包括localhost和127.0.0.1
mysql> create user 'chenzhongyang'@'%' identified by '123456';
mysql> create user 'chen'@'127.0.0.1' identified by '123456';
删除用户
mysql> drop user 'chenzhongyang'@'%';
Query OK, 0 rows affected (0.04 sec)
[root@test4 /]# mysql -uchen -p123456 -h127.0.0.1
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.1.70-log Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select user();
+----------------+
| user() |
+----------------+
| chen@localhost |
+----------------+
1 row in set (0.01 sec)
刚刚创建的用户的权限是usage
mysql> show grants;
+-------------------------------------------------------------------------------------------------------------+
| Grants for chen@127.0.0.1 |
+-------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'chen'@'127.0.0.1' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9' |
+-------------------------------------------------------------------------------------------------------------+
1 row in set (0.02 sec)
修改用户名，这个时候密码和权限没有变化
mysql> rename user 'chen'@'127.0.0.1' to 'chenzhongyang'@'127.0.0.1';
二，匿名用户
创建匿名用户之后，那么任何机器的任何用户都可以登录到mysql，所以这样很危险
mysql> insert into user(host,user,password) values('%','','');
Query OK, 1 row affected, 3 warnings (0.17 sec)
mysql> flush privileges; 刷新权限将重新加载user表的内容
Query OK, 0 rows affected (0.03 sec)
三，授权用户
例子如下
mysql> grant select on mysql.user to 'chenzhongyang'@'127.0.0.1' identified by '123456';
Query OK, 0 rows affected (0.32 sec)
[root@test4 /]# mysql -uchenzhongyang -p123456 -h127.0.0.1
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.1.70-log Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
mysql> select host from mysql.user where user='chenzhongyang';
+-----------+
| host |
+-----------+
| 127.0.0.1 |
+-----------+
1 row in set (0.04 sec)
授权的范围
回收权限
资源限制