数据库建模：学生信息系统搭建实验

首先必须理清学生信息系统有哪些实体，这些实体之间的关系又是如何的，他们之间是怎么进行关联的

实体有哪些：
学生表（student）
专业表（major）
课程表（course）
成绩表（grade）
班级表（class）
老师表（teacher）
宿舍表（dorm）
考勤表（checking）

这里我用Visio画的数据库ER图来分析：
大致实体ER图：

详细ER图：

二、数据库建模（建表）：

1、创建专业表（major）:

create table major(id int primary key auto_increment,name char(20)) charset=utf8;

数据表结构如下:

2、创建课程表（course）

create table course(id int primary key auto_increment,name char(20)) charset=utf8;

数据表结构如下:

3、创建专业和课程的中间表（major_mid_course）

create table major_mid_course(
id int primary key auto_increment,major_id int,
course_id int,
foreign key(major_id)references major(id),
foreign key(course_id) references course(id)
);

数据表结构如下:

4、创建成绩表（grade）

create table grade(
id int primary key auto_increment,
score int,stu_id int,course_id int,
foreign key(course_id) references course(id),
foreign key(stu_id) references student(id)
) charset=utf8;

数据表结构如下:

5、班级表（class）

create table class(
id int primary key auto_increment,
name char(20),
major_id int,foreign key(major_id) references major(id)
) charset=utf8;

数据表结构如下：

6、老师表（teacher）

create table teacher(id int primary key auto_increment,name char(20)) charset=utf8;

数据表结构如下：

7、班级和老师的中间表（class_teacher）

create table class_teacher(
id int primary key auto_increment,
class_id int,
tea_id int,
foreign key(class_id) references class(id),
foreign key(tea_id) references teacher(id)
);

数据表结构如下：

8、课程和老师的中间表（course_teacher）

create table course_teacher(
id int primary key auto_increment,
course_id int,
tea_id int,
foreign key(course_id) references course(id),
foreign key(tea_id) references teacher(id)
);

数据表结构如下：

9、宿舍表（drom）

create table drom(id int primary key auto_increment,name char(20)) charset=utf8;

数据表结构如下：

10、学生表（student）

create table student(
id int primary key auto_increment,
stu_num char(24),
name char(24),
age int,
gender char(20),
phone char(20),
major_id int,
class_id int,
drom_id int,
foreign key(major_id) references major(id),
foreign key(class_id) references class(id),
foreign key(drom_id) references drom(id)
) charset=utf8;

数据表结构如下：

11、学生和老师的中间表（student_teacher）

create table student_teacher(
id int primary key auto_increment,
stu_id int,
tea_id int,
foreign key(stu_id) references student(id),
foreign key(tea_id) references teacher(id)
);

数据表结构如下：

12、创建考勤表（checking）

create table checking(
id int primary key auto_increment,
date datetime,
status char(1),
stu_id int,foreign key(stu_id) references student(id)
) charset=utf8;

数据表结构如下:

二、数据插入：

1、插入专业表（major）数据

id	name
1	python
2	java
3	ui
4	php
5	linux

使用python来插入数据


2、插入课程表（course）数据

id	name
1	计算机基础
2	python基础
3	java编程
4	ps
5	html
6	数据库
7	linux基础

3、插入专业和课程关系表（major_mid_course）数据

id	major_id	course_id
1	1	1
2	1	2
3	1	5
4	1	6
5	1	7
6	2	1
7	2	3
8	2	5
9	2	6
10	3	1
11	3	4
12	4	1
13	4	5
14	5	1
15	5	7

4、插入班级表（class）数据

id	name	major_id
1	py0506	1
2	ui0304	3

5、插入老师表（teacher）数据

id	name
1	张老师
2	边老师
3	申老师

6、插入班级-老师关系表（class_teacher）数据

id	class_id	tea_id
1	1	2
2	1	3
3	2	1

7、插入课程-老师关系表（course_teacher）数据

id	course_id	tea_id
1	1	3
2	2	3
3	5	2
4	6	2
5	4	1

8、插入宿舍表（drom）数据

id	name
1	101
2	102
3	103

9、插入学员表（student）数据

id	stu_num	name	age	gender	phone	major_id	class_id	drom_id
1	1001	小李	19	男	13333331001	1	1	2
2	1002	小张	20	男	13333331002	1	1	2
3	1003	小王	18	男	13333331003	1	1	2
4	1004	小东	19	男	13333331004	1	1	2
5	1005	小丽	17	女	13333331005	1	1	3
6	1006	小花	19	女	13333331006	1	1	3
7	1007	小夏	20	女	13333331007	1	1	3
8	1008	小美	18	女	13333331008	1	1	3
9	1009	小韩	19	男	13333331009	3	2	1
10	1010	小吴	22	男	13333331010	3	2	1
11	1011	小牛	19	男	13333331011	3	2	1
12	1012	小朱	18	男	13333331012	3	2	1

10、插入学员-老师关系表（student_teacher）数据

id	stu_id	tea_id
1	1	2
2	2	2
3	3	2
4	4	2
5	5	2
6	6	2
7	7	2
8	8	2
9	9	1
10	10	1
11	11	1
12	12	1
13	1	3
14	2	3
15	3	3
16	4	3
17	5	3
18	6	3
19	7	3
20	8	3

11、插入成绩表（grade）数据（这里只插入python基础课程成绩）

id	score	stu_id	course_id
1	87	1	2
2	98	2	2
3	88	3	2
4	65	4	2
5	77	5	2
6	66	6	2
7	89	7	2
8	78	8	2

12、插入考勤表（checking）数据

id	date	status	stu_id
1	2019-6-14 9:05:34	N	2
2	2019-6-14 8:40:55	Y	3
3	2019-6-14 8:59:55	N	4
4	2019-6-13 8:30:22	Y	4

三、数据库优化：
1、给student表的name字段创建索引，（由于学生查询频繁），加快查询速度：

2、给student表创建视图，实现安全性（虚表）

四、用户授权：
1、创建用户并设置密码

create user nhkj@'10.10.21.%' identified by '123';

2、授权用户访问student_view表的查询权限

五、查询一下条件语句
1、查询所有学员

 select name from student;

2、查询所有男生

select name from student where gender='男';

3、查询所有女生

select name from student where gender='女';

4、查询所有缺勤学员

select name from student where id in (select stu_id from checking where status='N');

5、查询所有python专业的学员

select s.name,m.name from student as s inner join major as m on s.major_id=m.id and m.id=1;

6、查询所有python专业上过python基础的学员
为演示效果，我将‘小花’这个学生取消和‘申老师’关系，由于‘申老师’是教python基础课程的，所有‘小花’就是所有python专业学生里唯一没有上过python基础课程的学生，剩下的7位都上过小花的id为6

 delete from student_teacher where stu_id=6;

SELECT
s.id AS s_id,
s.name AS s_name,
c.id AS c_id,
c.name AS c_name
FROM
student AS s
INNER JOIN student_teacher AS st
INNER JOIN teacher AS t
INNER JOIN course_teacher AS ct
INNER JOIN course AS c
WHERE
s.id=st.stu_id
AND
st.tea_id=t.id
AND
t.id=ct.tea_id
AND
ct.course_id=c.id
AND
c.id=2;

7、查询所有python 0506班所有学员

select s.id as s_id,s.name as s_name,c.id as c_id,c.name as c_name from student
 as s inner join class as c on s.class_id=c.id and c.id=1;

8、查询所有python 0506班所有学员python基础课成绩

select s.name as s_name,c.name as c_name,g.score from student as s inner join
course as c inner join grade as g where s.id=g.stu_id and g.course_id=c.id;

9、查询python 0506班任课老师

select c.id as c_name,c.name as c_name,t.id as t_name,t.name as t_name from
 class as c inner join class_teacher as ct inner join teacher as t where c.id=ct.class_id and ct.tea_id=t.id and c.id=1;

10、查询边老师教过的学员

select t.id as t_id,t.name as t_name,s.id as s_id,s.name as s_name from teacher as t inner join 
student_teacher as st inner join student as s where t.id=st.tea_id and st.stu_id=s.id and t.name='边老师';

11、查询边老师教过的班级

select t.id as t_id,t.name as t_name,c.id as c_id,c.name as c_name 
from class as c inner join class_teacher as ct inner join teacher as t 
where c.id=ct.class_id and ct.tea_id=t.id and t.name='边老师';

12、查询小王同学python基础课程的成绩

select s.id as s_id,s.name as s_name,c.name as c_name,g.score 
from student as s inner join grade as g inner join course as c 
where c.id=g.course_id and s.id=g.stu_id and g.course_id=2 and s.id=3;

13、查询所有python基础课程的学员成绩

select s.id as s_id,s.name as s_name,c.name as c_name,g.score
from student as s inner join grade as g inner join course as c 
where c.id=g.course_id and s.id=g.stu_id and g.course_id=2;

14、查询python 0506班所有的宿舍

select c.id as c_id,c.name as c_name,d.id as d_id,d.name as d_name
from class as c inner join student as s inner join drom as d 

where c.id=s.class_id and s.drom_id=d.id and c.id=1;

15、查询python 0506班 102宿舍的所有学生的成绩

select c.name as c_name,d.name as d_name,s.name as s_name,g.score 
from class as c inner join student as s inner join drom as d inner join grade as g 
where c.id=s.class_id and s.drom_id=d.id and g.stu_id=s.id and c.id=1 and d.id=2;

转载于:https://www.cnblogs.com/ilovepython/p/11068852.html