[17] MySQL数据库--学生管理系统数据库手写SQL实现

Posted 2020-12-21 itzixueba

目录

• MySQL数据库--学生管理系统数据库手写SQL实现
  • 数据库设计
  • 手写SQL实现

mysql数据库--学生管理系统数据库手写SQL实现

• 学生对象----> 学生表(student)
• 老师对象----> 老师表(teacher)
• 课程对象----> 课程表(course)
• 成绩对象----> 成绩表(score)
• 班级对象----> 班级表(前缀_class,因为user或class等英文单词是程序中的关键字.尽量不直接用)
• 等.....

数据库设计

• 设计参考上篇博客

• https://www.cnblogs.com/itzixueba/p/11610070.html

手写SQL实现

/*
MySQL: 手写的SQL语句.可直接执行
学生表,老师表,课程表,班级表,成绩表
*/

drop table if EXISTS  tbl_score;   -- 删除成绩
drop table if EXISTS  tbl_student; -- 删除学生
drop table if EXISTS  tbl_teacher; -- 删除老师
drop table if EXISTS  tbl_course;  -- 删除课程
drop table if EXISTS  tbl_class;   -- 删除班级


-- 学生对象(student): 唯一标识id,姓名,性别,年龄,生日,电话,地址,邮箱
create table tbl_student(
	id int primary key auto_increment,  #id自增
  sname varchar(50) not null,
  sex char(2),
  age int ,
  birthday date,
  phone VARCHAR(11),
  email varchar(50),
  addr  varchar(100)
);
-- 插入数据
insert into tbl_student values(default,‘张A‘,‘男‘,20,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘北京‘);
insert into tbl_student values(default,‘张B‘,‘男‘,20,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘北京‘);
insert into tbl_student values(default,‘赵C‘,‘女‘,21,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘天津‘);
insert into tbl_student values(default,‘赵D‘,‘女‘,21,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘天津‘);
insert into tbl_student values(default,‘钱E‘,‘女‘,21,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘上海‘);
insert into tbl_student values(default,‘钱F‘,‘男‘,17,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘上海‘);
insert into tbl_student values(default,‘孙G‘,‘男‘,16,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘杭州‘);
insert into tbl_student values(default,‘孙H‘,‘女‘,17,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘杭州‘);
insert into tbl_student values(default,‘李I‘,‘男‘,26,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘苏州‘);
insert into tbl_student values(default,‘李J‘,‘女‘,34,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘苏州‘);
insert into tbl_student values(default,‘周K‘,‘女‘,40,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘四川‘);
insert into tbl_student values(default,‘周L‘,‘男‘,32,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘四川‘);
insert into tbl_student values(default,‘吴M‘,‘女‘,16,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘广州‘);
insert into tbl_student values(default,‘吴N‘,‘女‘,20,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘广州‘);
insert into tbl_student values(default,‘郑O‘,‘男‘,22,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘重庆‘);
insert into tbl_student values(default,‘郑P‘,‘男‘,23,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘重庆‘);
insert into tbl_student values(default,‘王Q‘,‘女‘,24,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘北京‘);
insert into tbl_student values(default,‘王R‘,‘男‘,28,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘天津‘);
insert into tbl_student values(default,‘冯S‘,‘女‘,39,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘山东‘);
insert into tbl_student values(default,‘冯T‘,‘男‘,20,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘山东‘);
insert into tbl_student values(default,‘陈U‘,‘女‘,25,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘山西‘);
insert into tbl_student values(default,‘陈V‘,‘男‘,28,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘山西‘);
insert into tbl_student values(default,‘楚W‘,‘女‘,28,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘山西‘);
insert into tbl_student values(default,‘楚X‘,‘男‘,29,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘河北‘);
insert into tbl_student values(default,‘魏Y‘,‘女‘,22,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘河北‘);
insert into tbl_student values(default,‘魏Z‘,‘男‘,21,‘1980-04-03‘,‘18888888888‘,‘[e-mail]‘,‘河南‘);

#select * from tbl_student;



-- 老师对象(teacher): 唯一标识id,姓名,性别,年龄,电话
create table tbl_teacher(
	id int primary key auto_increment ,
	tname varchar(50) not null,
  sex char(2),
  age int,
  phone varchar(11)
);
insert into tbl_teacher values(default,‘成龙‘,‘男‘,58,‘1766666601‘);
insert into tbl_teacher values(default,‘黎明‘,‘男‘,58,‘1766666601‘);
insert into tbl_teacher values(default,‘孙俪‘,‘女‘,35,‘1766666601‘);
insert into tbl_teacher values(default,‘范冰冰‘,‘女‘,35,‘1766666601‘);

# select * from tbl_teacher

-- 课程对象(course): 唯一标识id,课程名,开课时间,课时数量
create table tbl_course(
	id int primary key auto_increment ,
	cname varchar(11) not null unique, #非空,唯一
	start_time datetime,
	count int 
);
insert into tbl_course values(default,‘人工智能AI‘,now(),80);
insert into tbl_course values(default,‘数据分析‘,now(),70);
insert into tbl_course values(default,‘爬虫‘,now(),60);
insert into tbl_course values(default,‘大数据‘,now(),90);


-- 班级对象(tbl_class) : 唯一标识id,班级编号,人数
create table tbl_class(
	id int primary key auto_increment,
  cname varchar(50),
  size  int # 班级人数
);

insert into tbl_class values(default,‘人工智能一班‘,30);
insert into tbl_class values(default,‘数据分析一班‘,30);
insert into tbl_class values(default,‘爬虫一班‘,30);
insert into tbl_class values(default,‘大数据‘,30);


-- 成绩对象(score) : id,分数,课程名, 学生名
create table tbl_score(
	id int primary key auto_increment,
  score float(4,1),
  s_id int not null,
	c_id int not null,
	foreign key(s_id) references tbl_student(id),  #建表时指定外键
  foreign key(c_id) references tbl_course(id)  #建表时指定外键
);

# 修改表添加外键
#alter table tbl_score add constraint FK_scoreid_courseid foreign key(c_id) references tbl_course(id);
-- 第1个人,第4门课
insert into tbl_score values (default,58,1,1);
insert into tbl_score values (default,89,1,1);
insert into tbl_score values (default,78,1,2);
insert into tbl_score values (default,65,1,3);
insert into tbl_score values (default,90,1,4);
-- 第2个人4门课
insert into tbl_score values (default,90,2,1);
insert into tbl_score values (default,54,2,2);
insert into tbl_score values (default,89,2,2);
insert into tbl_score values (default,87,2,3);
insert into tbl_score values (default,92,2,4);

-- 第3个人3门课
insert into tbl_score values (default,90,3,1);
insert into tbl_score values (default,89,3,2);
insert into tbl_score values (default,87,3,3);


-- 第4个人3门课
insert into tbl_score values (default,87,4,1);
insert into tbl_score values (default,86,4,2);
insert into tbl_score values (default,90,4,3);
insert into tbl_score values (default,67,4,4);

-- 第5个人4门课
insert into tbl_score values (default,98,5,1);
insert into tbl_score values (default,90,5,2);
insert into tbl_score values (default,78,5,3);
insert into tbl_score values (default,98,5,4);


# select * from tbl_score;




-- 删除主键和外键
# alter table 表名 drop foreign key 外键（区分大小写）;
# alter table 表名 drop primary key;
# alter  table tbl_score drop foreign key  FK_scoreid_courseid