课程作业
课程名称:数据库系统原理
作业次数:作业#4
学号:21281280
姓名:柯劲帆
班级:物联网2101班
指导老师:郝爽
修改日期:2024年4月14日
---
# 1. 题目1
> 一、 **视图设计与操作（上机检查）**
>
> 请针对你在作业#2中所设计的用户界面的数据需求
>
> 1）至少设计并创建行列子集视图、带表达式的视图和分组视图各一个，并将代码加入自己的建库脚本中。
>
> 2）编写测试代码，通过视图实现数据查询操作
>
> 3）对不同类别视图尝试进行数据修改和删除操作，看能否实现，分析其原因
>
> 4）在实验室报告中总结视图的主要作用。
## 1.1 & 1.2 & 1.3
**行列子集视图：**
```mysql
mysql> CREATE VIEW TrainSchedule AS
-> SELECT
-> Passbys.TrainID,
-> Stations.Name AS StationName,
-> Passbys.arrive_time
-> FROM
-> Passbys
-> JOIN
-> Stations ON Passbys.StationID = Stations.ID;
Query OK, 0 rows affected (0.01 sec)
mysql> SELECT *
-> FROM TrainSchedule
-> WHERE TrainID = 'G103';
+---------+--------------+---------------------+
| TrainID | StationName | arrive_time |
+---------+--------------+---------------------+
| G103 | 沧州西 | 2024-03-28 06:20:00 |
| G103 | 济南西 | 2024-03-28 08:01:00 |
| G103 | 徐州东 | 2024-03-28 09:07:00 |
| G103 | 宿州东 | 2024-03-28 09:28:00 |
| G103 | 蚌埠南 | 2024-03-28 09:56:00 |
| G103 | 南京南 | 2024-03-28 10:40:00 |
| G103 | 无锡南 | 2024-03-28 11:27:00 |
| G103 | 上海虹桥 | 2024-03-28 11:58:00 |
+---------+--------------+---------------------+
8 rows in set (0.00 sec)
mysql> UPDATE TrainSchedule
-> SET arrive_time = '2024-03-28 07:00:00'
-> WHERE TrainID = 'G103' AND StationName = '北京南';
Query OK, 0 rows affected (0.00 sec)
Rows matched: 0 Changed: 0 Warnings: 0
```
**带表达式的视图：**
```mysql
mysql> CREATE VIEW TrainStopsWithDuration AS
-> SELECT
-> Passbys.TrainID,
-> Stations.Name AS StationName,
-> Passbys.arrive_time,
-> Passbys.leave_time,
-> TIMESTAMPDIFF(MINUTE, Passbys.arrive_time, Passbys.leave_time) AS StayDuration
-> FROM
-> Passbys
-> JOIN
-> Stations ON Passbys.StationID = Stations.ID;
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT *
-> FROM TrainStopsWithDuration
-> WHERE TrainID = 'G103';
+---------+--------------+---------------------+---------------------+--------------+
| TrainID | StationName | arrive_time | leave_time | StayDuration |
+---------+--------------+---------------------+---------------------+--------------+
| G103 | 沧州西 | 2024-03-28 06:20:00 | 2024-03-28 06:20:00 | 0 |
| G103 | 济南西 | 2024-03-28 08:01:00 | 2024-03-28 08:04:00 | 3 |
| G103 | 徐州东 | 2024-03-28 09:07:00 | 2024-03-28 09:09:00 | 2 |
| G103 | 宿州东 | 2024-03-28 09:28:00 | 2024-03-28 09:33:00 | 5 |
| G103 | 蚌埠南 | 2024-03-28 09:56:00 | 2024-03-28 09:58:00 | 2 |
| G103 | 南京南 | 2024-03-28 10:40:00 | 2024-03-28 10:43:00 | 3 |
| G103 | 无锡南 | 2024-03-28 11:27:00 | 2024-03-28 11:29:00 | 2 |
| G103 | 上海虹桥 | 2024-03-28 11:58:00 | 2024-03-28 11:58:00 | 0 |
+---------+--------------+---------------------+---------------------+--------------+
8 rows in set (0.01 sec)
mysql> -- 尝试更新 TrainStopsWithDuration 视图
mysql> UPDATE TrainStopsWithDuration
-> SET StayDuration = 10
-> WHERE TrainID = 'G103' AND StationName = '北京南';
ERROR 1348 (HY000): Column 'StayDuration' is not updatable
```
**分组视图：**
创建：
```mysql
mysql> CREATE VIEW TrainRoutes AS
-> SELECT
-> Trains.ID AS TrainID,
-> TIMESTAMPDIFF(HOUR, MIN(Passbys.arrive_time), MAX(Passbys.leave_time)) AS TotalDuration
-> FROM
-> Trains
-> JOIN
-> Passbys ON Trains.ID = Passbys.TrainID
-> GROUP BY
-> Trains.ID;
Query OK, 0 rows affected (0.01 sec)
mysql> SELECT *
-> FROM TrainRoutes;
+---------+---------------+
| TrainID | TotalDuration |
+---------+---------------+
| G103 | 5 |
+---------+---------------+
1 row in set (0.01 sec)
mysql> DELETE FROM TrainRoutes
-> WHERE TrainID = 'G103';
ERROR 1288 (HY000): The target table TrainRoutes of the DELETE is not updatable
```
## 1.4
尝试通过视图进行数据修改或删除受限于视图的结构和 SQL 引擎的限制。
可更新的视图通常需要直接对应到单个底层表的列，且不能包含聚合函数、不同的数据源或其他复杂的 SQL 操作，如 DISTINCT、GROUP BY、ORDER BY 等。
此外，视图中的所有字段都必须直接来源于一个底层数据表，而且这个表中相应的字段必须允许被更新。
# 2. 题目2
> **二、 用户口令管理设计题**
>
> 用户注册与认证管理是数据库系统的基本功能，请为你在作业#2中选择的具体案例设计一个用户注册与认证中的口令管理解决方案，要求如下
>
> 1) 用户口令采用密文存储，采用不可逆加密算法加密，查资料了解现有的不可逆算法。
> 2) 设计用户修改密码流程，用VISO画出流程图
> 3) 设计用户密码重置业务流程（可以包含线下流程），用VISO画出业务流程图
## 2.1
常见的不可逆加密算法有
- **MD5**
- **HMAC**
- **SHA1**：默认会产生一个160位的信息摘要，SHA1加密算法的安全性要比MD5更高
- **SHA2**：（SHA-224、SHA-256、SHA-384、SHA-512，SHA后面的数字表示的是加密后的字符串长度），SHA2加密算法安全性比SHA1的要高。
- **bcrypt**：设计用于密码存储，对抗暴力破解攻击效果更好。
- **Argon2**: 这是一个较新的算法，获得了密码哈希竞赛的胜利，为抵抗大规模攻击提供了强有力的防御。
## 2.2
## 2.3
# 3. 题目3
> **三、 用户授权操作题（上机检查）**
>
> 为你在作业#2中选择的具体案例增加若干个数据库用户，并对各个用户进行相应的授权操作，至少应完成如下操作：
>
> 1) 创建用户
> 2) 为不同的用户授予和收回表级SELECT, INSERT, UPDATE, DELETE, ALL PRIVILEGES权限
> 3) 为不同的用户授予和收回属性列级的SELECT, INSERT, UPDATE的权限
> 4) 创建角色，并把角色授予用户或收回用户的某个角色
>
> 将以上语句写成单独的SQL脚本，上机实验调试通过，编写测试代码，测试权限设置或取消是否成功，并将调试结果截屏写入实验报告。
```mysql
DROP USER IF EXISTS 'ticketAgent'@'localhost';
DROP USER IF EXISTS 'stationManager'@'localhost';
DROP USER IF EXISTS 'adminUser'@'localhost';
DROP ROLE IF EXISTS 'ticketRole';
DROP ROLE IF EXISTS 'stationRole';
CREATE USER 'ticketAgent'@'localhost' IDENTIFIED BY 'password123';
CREATE USER 'stationManager'@'localhost' IDENTIFIED BY 'password123';
CREATE USER 'adminUser'@'localhost' IDENTIFIED BY 'password123';
GRANT SELECT, INSERT ON DBLab.Tickets TO 'ticketAgent'@'localhost';
GRANT ALL PRIVILEGES ON DBLab.Stations TO 'stationManager'@'localhost';
GRANT SELECT, INSERT, UPDATE, DELETE ON DBLab.* TO 'adminUser'@'localhost';
REVOKE INSERT ON DBLab.Tickets FROM 'ticketAgent'@'localhost';
GRANT SELECT(Price) ON DBLab.Tickets TO 'ticketAgent'@'localhost';
GRANT UPDATE(Name, City) ON DBLab.Stations TO 'stationManager'@'localhost';
CREATE ROLE 'ticketRole';
CREATE ROLE 'stationRole';
GRANT SELECT, INSERT ON DBLab.Tickets TO 'ticketRole';
GRANT SELECT, UPDATE ON DBLab.Stations TO 'stationRole';
GRANT 'ticketRole' TO 'ticketAgent'@'localhost';
GRANT 'stationRole' TO 'stationManager'@'localhost';
REVOKE 'ticketRole' FROM 'ticketAgent'@'localhost';
FLUSH PRIVILEGES;
```
执行结果：
```sh
$ mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 42
Server version: 8.0.33 MySQL Community Server - GPL
Copyright (c) 2000, 2023, Oracle and/or its affiliates.
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> source ./privilege.sql
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.02 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
mysql> exit
Bye
$ mysql -u ticketAgent -ppassword123
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 45
Server version: 8.0.33 MySQL Community Server - GPL
Copyright (c) 2000, 2023, Oracle and/or its affiliates.
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> use DBLab;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from Stations;
ERROR 1142 (42000): SELECT command denied to user 'ticketAgent'@'localhost' for table 'Stations'
mysql>
```
# 4. 题目4
> **四、 数据库完整性实验题**
>
> 完善作业#3中你的数据模型完整性设计，模型中至少应体现如下完整性要求：
>
> 1） 实体完整性
>
> 2） 参照完整性
>
> 3） 用户定义的完整性
>
> 4） 对部分完整性约束进行命名
>
> 5） 创建域以实现某些属性内容完整性
>
> 将以上实现代码加入到作业#3 的脚本中并调试通过，用违犯相应约束的语句尝试，以验证完整性约束实施效果。注意观察不同的RDBMS平台对完整性的支持程度。
原本的建表语句中已满足1、2、3。做如下修改：
```mysql
CREATE TABLE Passengers (
ID BIGINT PRIMARY KEY,
`Name` VARCHAR ( 255 ) NOT NULL,
Phone_number BIGINT UNIQUE NOT NULL,
CHECK ( REGEXP_LIKE ( ID, '^\\d{18}$' ) ),
CHECK ( REGEXP_LIKE ( Phone_number, '^\\d{11}$' ) )
);
```
对完整性约束进行命名：
```mysql
CREATE TABLE Passengers (
ID BIGINT PRIMARY KEY,
`Name` VARCHAR(255) NOT NULL,
Phone_number BIGINT UNIQUE NOT NULL,
CONSTRAINT CHK_ID_FORMAT CHECK (REGEXP_LIKE(ID, '^\\d{18}$')),
CONSTRAINT CHK_PHONE_FORMAT CHECK (REGEXP_LIKE(Phone_number, '^\\d{11}$'))
);
```
尝试违反：
```mysql
mysql> INSERT INTO Passengers (ID, `Name`, Phone_number) VALUES (123456789012345678, 'John Doe', 1234567890);
ERROR 3819 (HY000): Check constraint 'CHK_PHONE_FORMAT' is violated.
```
MySQL不直接支持域，但是可以通过`CHECK`约束来实现类似的功能。