视图

create view 视图名   as  查询语句;

MariaDB [hellodb]> create view view_left as select name from students;
Query OK, 0 rows affected (0.00 sec)
MariaDB [hellodb]> create view view_students as select stuid,name from students;Query OK, 0 rows affected (0.00 sec)

MariaDB [hellodb]> select * from view_students;
+-------+---------------+
| stuid | name          |
+-------+---------------+
|     1 | Shi Zhongyu   |
|     2 | Shi Potian    |
|     3 | Xie Yanke     |
|     4 | Ding Dian     |
|     5 | Yu Yutong     |
|     6 | Shi Qing      |
|     7 | Xi Ren        |
|     8 | Lin Daiyu     |
|     9 | Ren Yingying  |
|    10 | Yue Lingshan  |
|    11 | Yuan Chengzhi |
|    12 | Wen Qingqing  |
|    13 | Tian Boguang  |
|    14 | Lu Wushuang   |
|    15 | Duan Yu       |
|    16 | Xu Zhu        |
|    17 | Lin Chong     |
|    18 | Hua Rong      |
|    19 | Xue Baochai   |
|    20 | Diao Chan     |
|    21 | Huang Yueying |
|    22 | Xiao Qiao     |
|    23 | Ma Chao       |
|    24 | Xu Xian       |
|    25 | Sun Dasheng   |
+-------+---------------+
25 rows in set (0.00 sec)

用户管理

1、用户账号

用户的账号由用户名和HOST俩部分组成(\’USERNAME\’@\’HOST\’

HOST的表示:

  • 主机名

  • 具体IP地址
  • 网段/掩码

可以使用通配符表示,%和_;192.168.%即表示这个网段的所有主机

2、增加删除账号

主要:在数据库中修改了用户信息需要执行FLUSH PRIVILEGES;来刷新授权表使其生效

  • 创建

    create user \'用户名\'@\'主机名\' identified by \'密码\';
 MariaDB [mysql]> CREATE USER \'user1\'@\'192.168.%\';
  MariaDB [mysql]> CREATE USER \'user2\'@\'192.168.%\' IDENTIFIED BY \'your_password\';
  MariaDB [mysql]> SELECT user,host,password FROM user;
  +-------+-----------+-------------------------------------------+
  | user  | host      | password                                  |
  +-------+-----------+-------------------------------------------+
  | root  | localhost | *4A54C3F37C03C7FBACE31591D6A8C546F93DF5C5 |
  | root  | centos7   |                                           |
  | root  | 127.0.0.1 |                                           |
  | root  | ::1       |                                           |
  |       | localhost |                                           |
  |       | centos7   |                                           |
  | user1 | 192.168.% |                                           |
  | user2 | 192.168.% | *9E72259BA9214F692A85B240647C4D95B0F2E08B |
  +-------+-----------+-------------------------------------------+
  • 删除

    drop user \'用户名\'@\'主机名\';
     MariaDB [mysql]> DROP USER user2@\'192.168.%\';
  MariaDB [mysql]> SELECT user,host,password FROM user;      
  +-------+-----------+-------------------------------------------+
  | user  | host      | password                                  |
  +-------+-----------+-------------------------------------------+
  | root  | localhost | *4A54C3F37C03C7FBACE31591D6A8C546F93DF5C5 |
  | root  | centos7   |                                           |
  | root  | 127.0.0.1 |                                           |
  | root  | ::1       |                                           |
  |       | localhost |                                           |
  |       | centos7   |                                           |
  | user1 | 192.168.% |                                           |
  +-------+-----------+-------------------------------------------+
  • 重命名
MariaDB [mysql]> RENAME USER user1@\'192.168.%\' TO testuser@\'%\';
  MariaDB [mysql]> SELECT user,host,password FROM mysql.user;
  +----------+-----------+-------------------------------------------+
  | user     | host      | password                                  |
  +----------+-----------+-------------------------------------------+
  | root     | localhost | *4A54C3F37C03C7FBACE31591D6A8C546F93DF5C5 |
  | root     | centos7   |                                           |
  | root     | 127.0.0.1 |                                           |
  | root     | ::1       |                                           |
  |          | localhost |                                           |
  |          | centos7   |                                           |
  | testuser | %         |                                           |
  +----------+-----------+-------------------------------------------+
修改密码
 MariaDB [mysql]> SET PASSWORD FOR testuser@\'%\' =PASSWORD(\'testpass\');
 MariaDB [mysql]> SELECT user,host,password FROM mysql.user;          
  +----------+-----------+-------------------------------------------+
  | user     | host      | password                                  |
  +----------+-----------+-------------------------------------------+
  | root     | localhost | *4A54C3F37C03C7FBACE31591D6A8C546F93DF5C5 |
  | root     | centos7   |                                           |
  | root     | 127.0.0.1 |                                           |
  | root     | ::1       |                                           |
  |          | localhost |                                           |
  |          | centos7   |                                           |
  | testuser | %         | *00E247AC5F9AF26AE0194B41E1E769DEE1429A29 |
  +----------+-----------+-------------------------------------------+

其他修改密码的方法:

​ UPDATE user SET password=PASSWORD(\'testpass\') WHERE user=\'testuser\';

​ # mysqladmin -uroot -poldpass password \'newpass\'

3、破解管理账号密码

  • 空数据库的情况下恢复密码
# systemctl stop mariadb
  # rm -rf /var/lib/mysql/*  #删库跑路
  # systemctl start mariadb
  • 有数据的情况下恢复密码
  1)在/etc/my.cnf配置文件的[mydqld]下添加skip-grant-tables和skip-networking参数
  2)# systemctl restart mariadb 重启服务
  3)执行mysql登录到数据库
  4)MariaDB [(none)]> UPDATE mysql.user SET password=PASSWORD(\'newpassword\') WHERE user=\'root\' AND host=\'localhost\';  #更新密码
  5)MariaDB [(none)]> FLUSH PRIVILEGES;  #刷新授权表
  6)退出,修改配置文件,删除skip-grant-tables和skip-networking参数,重启服务

也可以在启动mysqld进程时,为其使用如下选项:
--skip-grant-tables

​ --skip-networking

授权管理

1、授权

grant all on 库名.标名(*表示所有) to 用户名@\'主机名(%所有)\' identified by \'密码\'; 

授权时如果用户不存在则创建,所以我们一般不会单独去创建一个用户,而是授权创建一块完成。

  • priv_type 授权类型
    SELECT
    ​INSERT
    ​UPDATE
    ​DELETE
    ​CREATE
    ​DROP
    INDEX
    ALTER
    ​SHOW DATABASES
    ​CREATE TEMPORARY TABLES
    ​LOCK TABLES
    ​CREATE VIEW
    SHOW VIEW
    CREATE USER
    ALL PRIVILEGES 或 ALL
  • object_type 授权对象
    TABLE
    FUNCTION
    PROCEDURE
  • priv_level 授权级别
    *或*.* 表示所有库
    db_name.* 表示指定库中的所有表
    db_name.tbl_name 指定库中的指定表
    tbl_name 表示当前库的表
    db_name.routine_name 表示指定库的函数,存储过程,触发器
  • WITH GRANT OPTION
    MAX_QUERIES_PER_HOUR count
    MAX_UPDATES_PER_HOUR count
    MAX_CONNECTIONS_PER_HOUR count
    MAX_USER_CONNECTIONS count
MariaDB [school]> GRANT SELECT(stuid,name) ON TABLE school.students TO admin@\'%\' IDENTIFIED BY \'admin\';  #把students表的stuid和name字段的查询权限授权于admin@\'%\'用户
MariaDB [school]> FLUSH PRIVILEGES;  #刷新授权表

2、查询授权

MariaDB [school]> SHOW GRANTS FOR admin@\'%\'\G  #查看指定用户的权限
*************************** 1. row ***************************
Grants for admin@%: GRANT USAGE ON *.* TO \'admin\'@\'%\' IDENTIFIED BY PASSWORD \'*4ACFE3202A5FF5CF467898FC58AAB1D615029441\'
*************************** 2. row ***************************
Grants for admin@%: GRANT SELECT (stuid, name) ON `school`.`students` TO \'admin\'@\'%\'
[root@working ~]# mysql -uadmin -padmin -h192.168.0.7
MariaDB [(none)]> SHOW GRANTS FOR CURRENT_USER()\G  #查询自己的权限
*************************** 1. row ***************************
Grants for admin@%: GRANT USAGE ON *.* TO \'admin\'@\'%\' IDENTIFIED BY PASSWORD \'*4ACFE3202A5FF5CF467898FC58AAB1D615029441\'
*************************** 2. row ***************************
Grants for admin@%: GRANT SELECT (stuid, name) ON `school`.`students` TO \'admin\'@\'%\'

3、收回授权

MariaDB [school]> REVOKE SELECT(stuid) ON school.students FROM admin@\'%\';  #收回admin@\'%\'用户对stuid字段的查询权限

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