【MySQL】视图与用户管理
目录
- 一、视图
-
- 1.1 视图概念
- 1.2 使用
- 1.3 基表与视图的相互影响
- 二、用户管理
- 2.1 新增用户
- 2.2 删除
- 2.3 修改密码
- 三、用户权限
-
- 3.1 授予权限
- 3.2 修改权限
一、视图
1.1 视图概念
视图就是一张虚拟表，其内容由查询定义。与真实的表一样，视图包含一系列带有名称的列和行数据。视图的数据变化影响到基表，基表的数据变化也会影响到视图
1.2 使用
- 创建视图
create view 视图名 as select语句；
如：为emp表和dept表建立表内连接
mysql> create view myview as select ename,dname from emp inner join deptt on emp.deptno=dept.deptno;
- 删除视图
drop view 视图名；
把select查出来的东西变成了临时表结构，放在表之中，这个表就是视图。好处就是获取一些高频访问的数据时，不用在做多表查询了，直接以视图的方式查看即可
1.3 基表与视图的相互影响
二者相互影响，任何一方的修改都会影响另一方
--查询myview
mysql> select * from myview;
+--------+------------+
| ename | dname |
+--------+------------+
| SMITH | RESEARCH |
| ALLEN | SALES |
| WARD | SALES |
| JONES | RESEARCH |
| MARTIN | SALES |
| BLAKE | SALES |
| CLARK | ACCOUNTING |
| SCOTT | RESEARCH |
| KING | ACCOUNTING |
| TURNER | SALES |
| ADAMS | RESEARCH |
| JAMES | SALES |
| FORD | RESEARCH |
| MILLER | ACCOUNTING |
+--------+------------+
14 rows in set (0.00 sec)
-- 查询emp表
mysql> select * from emp;
+--------+--------+-----------+------+---------------------+---------+---------+--------+
| empno | ename | job | mgr | hiredate | sal | comm | deptno |
+--------+--------+-----------+------+---------------------+---------+---------+--------+
| 007369 | SMITH | CLERK | 7902 | 1980-12-17 00:00:00 | 800.00 | NULL | 20 |
| 007499 | ALLEN | SALESMAN | 7698 | 1981-02-20 00:00:00 | 1600.00 | 300.00 | 30 |
| 007521 | WARD | SALESMAN | 7698 | 1981-02-22 00:00:00 | 1250.00 | 500.00 | 30 |
| 007566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL | 20 |
| 007654 | MARTIN | SALESMAN | 7698 | 1981-09-28 00:00:00 | 1250.00 | 1400.00 | 30 |
| 007698 | BLAKE | MANAGER | 7839 | 1981-05-01 00:00:00 | 2850.00 | NULL | 30 |
| 007782 | CLARK | MANAGER | 7839 | 1981-06-09 00:00:00 | 2450.00 | NULL | 10 |
| 007788 | SCOTT | ANALYST | 7566 | 1987-04-19 00:00:00 | 3000.00 | NULL | 20 |
| 007839 | KING | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 | NULL | 10 |
| 007844 | TURNER | SALESMAN | 7698 | 1981-09-08 00:00:00 | 1500.00 | 0.00 | 30 |
| 007876 | ADAMS | CLERK | 7788 | 1987-05-23 00:00:00 | 1100.00 | NULL | 20 |
| 007900 | JAMES | CLERK | 7698 | 1981-12-03 00:00:00 | 950.00 | NULL | 30 |
| 007902 | FORD | ANALYST | 7566 | 1981-12-03 00:00:00 | 3000.00 | NULL | 20 |
| 007934 | MILLER | CLERK | 7782 | 1982-01-23 00:00:00 | 1300.00 | NULL | 10 |
+--------+--------+-----------+------+---------------------+---------+---------+--------+
14 rows in set (0.00 sec)
--修改一行数据 SMITH -》 smith
mysql> update emp set ename='smith' where ename='SMITH';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
-- 查询发现 emp被修改
mysql> select * from emp;
+--------+--------+-----------+------+---------------------+---------+---------+--------+
| empno | ename | job | mgr | hiredate | sal | comm | deptno |
+--------+--------+-----------+------+---------------------+---------+---------+--------+
| 007369 | smith | CLERK | 7902 | 1980-12-17 00:00:00 | 800.00 | NULL | 20 |
| 007499 | ALLEN | SALESMAN | 7698 | 1981-02-20 00:00:00 | 1600.00 | 300.00 | 30 |
| 007521 | WARD | SALESMAN | 7698 | 1981-02-22 00:00:00 | 1250.00 | 500.00 | 30 |
| 007566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL | 20 |
| 007654 | MARTIN | SALESMAN | 7698 | 1981-09-28 00:00:00 | 1250.00 | 1400.00 | 30 |
| 007698 | BLAKE | MANAGER | 7839 | 1981-05-01 00:00:00 | 2850.00 | NULL | 30 |
| 007782 | CLARK | MANAGER | 7839 | 1981-06-09 00:00:00 | 2450.00 | NULL | 10 |
| 007788 | SCOTT | ANALYST | 7566 | 1987-04-19 00:00:00 | 3000.00 | NULL | 20 |
| 007839 | KING | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 | NULL | 10 |
| 007844 | TURNER | SALESMAN | 7698 | 1981-09-08 00:00:00 | 1500.00 | 0.00 | 30 |
| 007876 | ADAMS | CLERK | 7788 | 1987-05-23 00:00:00 | 1100.00 | NULL | 20 |
| 007900 | JAMES | CLERK | 7698 | 1981-12-03 00:00:00 | 950.00 | NULL | 30 |
| 007902 | FORD | ANALYST | 7566 | 1981-12-03 00:00:00 | 3000.00 | NULL | 20 |
| 007934 | MILLER | CLERK | 7782 | 1982-01-23 00:00:00 | 1300.00 | NULL | 10 |
+--------+--------+-----------+------+---------------------+---------+---------+--------+
14 rows in set (0.00 sec)
-- 查询发现 myview也被修改
mysql> select * from myview;
+--------+------------+
| ename | dname |
+--------+------------+
| smith | RESEARCH |
| ALLEN | SALES |
| WARD | SALES |
| JONES | RESEARCH |
| MARTIN | SALES |
| BLAKE | SALES |
| CLARK | ACCOUNTING |
| SCOTT | RESEARCH |
| KING | ACCOUNTING |
| TURNER | SALES |
| ADAMS | RESEARCH |
| JAMES | SALES |
| FORD | RESEARCH |
| MILLER | ACCOUNTING |
+--------+------------+
14 rows in set (0.00 sec)
-- 同理 修改 任何一方 另一方也会改变 这里不在演示
二、用户管理
mysql> use mysql
mysql> select USER,HOST,authentication_string from user;
+---------------+-----------+-------------------------------------------+
| USER | HOST | authentication_string |
+---------------+-----------+-------------------------------------------+
| root | localhost | *5A735A4D91144BD631C02B4F2491B12EE292AB09 |
| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
+---------------+-----------+-------------------------------------------+
3 rows in set (0.00 sec)
2.1 新增用户
对用户的增删改操作可以用mysql提供的专门对用户管理的sql语句，也可以使用DML语言
create user '用户名'@'登陆主机/ip' identified by '密码';
mysql> create user 'zzg'@'localhost' identified by '123456';
Query OK, 0 rows affected (0.00 sec)
mysql> select USER,HOST,authentication_string from user;
+---------------+-----------+-------------------------------------------+
| USER | HOST | authentication_string |
+---------------+-----------+-------------------------------------------+
| root | localhost | *FC92B1E8372C68199223915FC5AFE0C3BF2D64E6 |
| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| zzg | localhost | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
+---------------+-----------+-------------------------------------------+
4 rows in set (0.00 sec)
使用windows客户端连接云服务器上的数据库
如果发现赋操作没有生效，执行如下指令flush privileges;
2.2 删除
drop user '用户名'@'主机名'
mysql> drop user 'zzg'@'localhost';
Query OK, 0 rows affected (0.00 sec)
mysql> select USER,HOST,authentication_string from user;
+---------------+-----------+-------------------------------------------+
| USER | HOST | authentication_string |
+---------------+-----------+-------------------------------------------+
| root | localhost | *FC92B1E8372C68199223915FC5AFE0C3BF2D64E6 |
| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
+---------------+-----------+-------------------------------------------+
3 rows in set (0.00 sec)
2.3 修改密码
1.自己改自己的
set password=password('新的密码');
2.root修改任意的
set password for '用户名'@'主机名'=password('新的密码');
3.DML对表中数据操作
update user set authentication_string=password('666666') where user='wmh';
4.修改用户的允许登录的ip
update user set host = '%' where user = '用户名';
三、用户权限
3.1 授予权限
刚创建的用户没有任何权限。需要给用户授权
语法：
grant 权限列表 on 库.对象名 to '用户名'@'登陆位置' [identified by '密码']
查看用户权限：
show grants for '用户名'@'登陆位置';
权限列表，多个权限用逗号分开
grant select on ...
grant select, delete, create on ....
grant all [privileges] on ... -- 表示赋予该用户在该对象上的所有权限
*.* : 代表本系统中的所有数据库的所有对象（表，视图，存储过程等）
库.* : 表示某个数据库中的所有数据对象(表，视图，存储过程等)
示例：
--给用户赋予soctt数据库下所有文件的select权限
mysql> grant all on scott.* to 'zzg'@'localhost';
mysql> show grants for 'zzg'@'%';--查询用户现有权限
+------------------------------------------------+
| Grants for wmh@% |
+------------------------------------------------+
| GRANT USAGE ON *.* TO 'wmh'@'%' |--连接登录权限
| GRANT ALL PRIVILEGES ON `scott`.* TO 'wmh'@'%' |--scott数据库下所有权限
3.2 修改权限
语法：
revoke 权限列表 on 库.对象名 from '用户名'@'登陆位置'；
示例：
回收zzg用户在scott数据库所有表的删除权限，即无法再进行删除数据
revoke delete on scott.* from 'zzg'@'%';