JavaWeb开发教程：2023.3.29坚持第31天，MySQL数据库开发设计

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记录时间：2023.3.29

已坚持学习第31天

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JavaWeb-MySQL数据库设计总结

完成代码练习

1.SQL数据库设计

-- 员工管理
create table tb_emp (
id int unsigned primary key auto_increment comment 'ID',
username varchar(20) not null unique comment '用户名',
password varchar(32) default '123456' comment '密码',
name varchar(10) not null comment '姓名',
gender tinyint unsigned not null comment '性别, 说明: 1 男, 2 女',
image varchar(300) comment '图像',
job tinyint unsigned comment '职位, 说明: 1 班主任,2 讲师, 3 学工主管, 4 教研主管',
entrydate date comment '入职时间',
create_time datetime not null comment '创建时间',
update_time datetime not null comment '修改时间'
) comment '员工表';
INSERT INTO tb_emp
(id, username, password, name, gender, image, job, entrydate, create_time, update_time) VALUES
(1,'jinyong','123456','金庸',1,'1.jpg',4,'2000-01-01',now(),now()),
(2,'zhangwuji','123456','张无忌',1,'2.jpg',2,'2015-01-01',now(),now()),
(3,'yangxiao','123456','杨逍',1,'3.jpg',2,'2008-05-01',now(),now()),
(4,'weiyixiao','123456','韦一笑',1,'4.jpg',2,'2007-01-01',now(),now()),
(5,'changyuchun','123456','常遇春',1,'5.jpg',2,'2012-12-05',now(),now()),
(6,'xiaozhao','123456','小昭',2,'6.jpg',3,'2013-09-05',now(),now()),
(7,'jixiaofu','123456','纪晓芙',2,'7.jpg',1,'2005-08-01',now(),now()),
(8,'zhouzhiruo','123456','周芷若',2,'8.jpg',1,'2014-11-09',now(),now()),
(9,'dingminjun','123456','丁敏君',2,'9.jpg',1,'2011-03-11',now(),now()),
(10,'zhaomin','123456','赵敏',2,'10.jpg',1,'2013-09-05',now(),now()),
(11,'luzhangke','123456','鹿杖客',1,'11.jpg',2,'2007-02-01',now(),now()),
(12,'hebiweng','123456','鹤笔翁',1,'12.jpg',2,'2008-08-18',now(),now()),
(13,'fangdongbai','123456','方东白',1,'13.jpg',1,'2012-11-01',now(),now()),
(14,'zhangsanfeng','123456','张三丰',1,'14.jpg',2,'2002-08-01',now(),now()),
(15,'yulianzhou','123456','俞莲舟',1,'15.jpg',2,'2011-05-01',now(),now()),
(16,'songyuanqiao','123456','宋远桥',1,'16.jpg',2,'2010-01-01',now(),now()),
(17,'chenyouliang','12345678','陈友谅',1,'17.jpg',NULL,'2015-03-21',now(),now()),
(18,'zhang1','123456','张一',1,'2.jpg',2,'2015-01-01',now(),now()),
(19,'zhang2','123456','张二',1,'2.jpg',2,'2012-01-01',now(),now()),
(20,'zhang3','123456','张三',1,'2.jpg',2,'2018-01-01',now(),now()),
(21,'zhang4','123456','张四',1,'2.jpg',2,'2015-01-01',now(),now()),
(22,'zhang5','123456','张五',1,'2.jpg',2,'2016-01-01',now(),now()),
(23,'zhang6','123456','张六',1,'2.jpg',2,'2012-01-01',now(),now()),
(24,'zhang7','123456','张七',1,'2.jpg',2,'2006-01-01',now(),now()),
(25,'zhang8','123456','张八',1,'2.jpg',2,'2002-01-01',now(),now()),
(26,'zhang9','123456','张九',1,'2.jpg',2,'2011-01-01',now(),now()),
(27,'zhang10','123456','张十',1,'2.jpg',2,'2004-01-01',now(),now()),
(28,'zhang11','123456','张十一',1,'2.jpg',2,'2007-01-01',now(),now()),
(29,'zhang12','123456','张十二',1,'2.jpg',2,'2020-01-01',now(),now());
-- ====================================> DQL <=======================================
--  =================== 基本查询 ======================
-- 1. 查询指定字段 name,entrydate 并返回
select name,entrydate from tb_emp ;
-- 2. 查询返回所有字段
-- 方式一:  推荐 , 效率高 . 更直观
select id, username, password, name, gender, image, job, entrydate, create_time, update_time from tb_emp;
-- 方式二:
select * from tb_emp;
-- 3. 查询所有员工的 name,entrydate, 并起别名(姓名、入职日期)  --- as 关键字可以省略
select name as '姓名' ,entrydate as '入职日期' from tb_emp ;
select name '姓名' ,entrydate '入职日期' from tb_emp ;
-- 4. 查询员工有哪几种职位(不要重复) -- distinct
select distinct job from tb_emp;
select * from tb_emp where id = 1;
--  =================== 条件查询 ======================
-- 1. 查询 姓名 为 杨逍 的员工
select * from tb_emp where name = '杨逍';
-- 2. 查询在 id小于等于5 的员工信息
select * from tb_emp where id <= 5;
-- 3. 查询 没有分配职位 的员工信息  -- 判断 null , 用 is null
select * from tb_emp where job is null;
-- 4. 查询 有职位 的员工信息  -- 判断 不是null , 用 is not null
select * from tb_emp where job is not null ;
-- 5. 查询 密码不等于 '123456' 的员工信息
select * from tb_emp where password <> '123456';
select * from tb_emp where password != '123456';
-- 6. 查询入职日期 在 '2000-01-01' (包含) 到 '2010-01-01'(包含) 之间的员工信息
select * from tb_emp where entrydate between '2000-01-01' and '2010-01-01' ;
-- 7. 查询 入职时间 在 '2000-01-01' (包含) 到 '2010-01-01'(包含) 之间 且 性别为女 的员工信息
select * from tb_emp where (entrydate between '2000-01-01' and '2010-01-01') and  gender = 2;
-- 8. 查询 职位是 2 (讲师), 3 (学工主管), 4 (教研主管) 的员工信息
select * from tb_emp where job = 2 or job = 3 or job = 4;
select * from tb_emp where job in (2,3,4);
-- 9. 查询姓名为两个字的员工信息
select * from tb_emp where name like '__';
-- 10. 查询姓 '张' 的员工信息  ---------> 张%
select * from tb_emp where name like '张%';
-- 11. 查询姓名中包含 '三' 的员工信息
select * from tb_emp where name like '%三%';
-- 练习 : 员工管理列表查询
-- 条件 : name , gender , entrydate
select * from tb_emp where name like '%张%' and gender = 1 and entrydate between '2000-01-01' and '2010-01-01';
--  =================== 排序查询 ======================
-- 1. 根据入职时间, 对员工进行升序排序  -- 排序条件
select * from tb_emp order by entrydate asc ; -- 默认升序, asc可以省略的
select * from tb_emp order by entrydate ;
-- 2. 根据入职时间, 对员工进行降序排序
select * from tb_emp order by entrydate desc;
-- 3. 根据 入职时间 对公司的员工进行 升序排序 ， 入职时间相同 , 再按照 ID 进行降序排序
select * from tb_emp order by entrydate asc , id desc ;
-- 练习 : 员工管理列表查询 , 根据最后操作时间, 进行倒序排序
-- 条件 : name , gender , entrydate
select * from tb_emp where name like '%张%' and gender = 1 and entrydate between '2000-01-01' and '2010-01-01' order by update_time desc;
--  =================== 分页查询 ======================
-- 1. 查询第1页员工数据, 每页展示10条记录
select * from tb_emp limit 0,10;
select * from tb_emp limit 10;
-- 2. 查询第2页员工数据, 每页展示10条记录
select * from tb_emp limit 10,10;
-- 公式 : 页码 ---> 起始索引  ------->  起始索引 = (页码 - 1) * 每页记录数
-- 练习 : 员工管理列表查询 , 根据最后操作时间, 进行倒序排序
-- 条件 : name , gender , entrydate
select * from tb_emp where name like '%张%' and gender = 1 and entrydate between '2000-01-01' and '2010-01-01' order by update_time desc limit 0,10 ;
--  =================== 分组查询 ======================
-- 聚合函数
-- 1. 统计该企业员工数量 -- count
-- A. count(字段)
select count(id) from tb_emp;
select count(job) from tb_emp; -- null值不参与聚合函数运算
-- B. count(*)
select count(*) from tb_emp;
-- C. count(值)
select count(1) from tb_emp;
-- 2. 统计该企业员工 ID 的平均值
select avg(id) from tb_emp;
-- 3. 统计该企业最早入职的员工的入职日期
select min(entrydate) from tb_emp;
-- 4. 统计该企业最近入职的员工的入职日期
select max(entrydate) from tb_emp;
-- 5. 统计该企业员工的 ID 之和
select sum(id) from tb_emp;
-- 分组
-- 1. 根据性别分组 , 统计男性和女性员工的数量  -- count
select gender , count(*) from tb_emp group by gender;
-- 2. 先查询入职时间在 '2015-01-01' (包含) 以前的员工 , 并对结果根据职位分组 , 获取员工数量大于等于2的职位 -- count
select job ,count(*)  from tb_emp where entrydate <= '2015-01-01'  group by job having count(*) >= 2;
-- 男性与女性员工的人数统计 (1 : 男性员工 , 2 : 女性员工)
-- 函数: if(条件表达式 , t , f)
select
if(gender = 1, '男性员工' , '女性员工') '性别',
count(*) '人数'
from tb_emp group by gender;
-- 员工职位信息 -- count
-- 函数: case when ... then ... when ... then ... else ... end
-- 函数: case ... when ... then ... when ... then ... else ... end
select
(case when job = 1 then '班主任' when job = 2 then '讲师' when job = 3 then '教研主管' when job = 4 then '学工主管' else '无职位' end ) '职位',
count(*)
from tb_emp group by job;
select
(case job when 1 then '班主任' when 2 then '讲师' when 3 then '教研主管' when 4 then '学工主管' else '无职位' end ) '职位',
count(*)
from tb_emp group by job;

2.多表设计

-- 员工
create table tb_emp (
id int unsigned primary key auto_increment comment 'ID',
username varchar(20) not null unique comment '用户名',
password varchar(32) default '123456' comment '密码',
name varchar(10) not null comment '姓名',
gender tinyint unsigned not null comment '性别, 说明: 1 男, 2 女',
image varchar(300) comment '图像',
job tinyint unsigned comment '职位, 说明: 1 班主任,2 讲师, 3 学工主管, 4 教研主管',
entrydate date comment '入职时间',
dept_id int unsigned comment '归属的部门ID',
create_time datetime not null comment '创建时间',
update_time datetime not null comment '修改时间'
) comment '员工表';
-- 部门
create table tb_dept (
id int unsigned primary key auto_increment comment 'ID',
name varchar(10) not null unique comment '部门名称',
create_time datetime not null comment '创建时间',
update_time datetime not null comment '修改时间'
) comment '部门表';
-- 插入测试数据
insert into tb_dept (id, name, create_time, update_time) values
(1,'学工部',now(),now()),(2,'教研部',now(),now()),(3,'咨询部',now(),now()),
(4,'就业部',now(),now()),(5,'人事部',now(),now());
INSERT INTO tb_emp
(id, username, password, name, gender, image, job, entrydate,dept_id, create_time, update_time) VALUES
(1,'jinyong','123456','金庸',1,'1.jpg',4,'2000-01-01',2,now(),now()),
(2,'zhangwuji','123456','张无忌',1,'2.jpg',2,'2015-01-01',2,now(),now()),
(3,'yangxiao','123456','杨逍',1,'3.jpg',2,'2008-05-01',2,now(),now()),
(4,'weiyixiao','123456','韦一笑',1,'4.jpg',2,'2007-01-01',2,now(),now()),
(5,'changyuchun','123456','常遇春',1,'5.jpg',2,'2012-12-05',2,now(),now()),
(6,'xiaozhao','123456','小昭',2,'6.jpg',3,'2013-09-05',1,now(),now()),
(7,'jixiaofu','123456','纪晓芙',2,'7.jpg',1,'2005-08-01',1,now(),now()),
(8,'zhouzhiruo','123456','周芷若',2,'8.jpg',1,'2014-11-09',1,now(),now()),
(9,'dingminjun','123456','丁敏君',2,'9.jpg',1,'2011-03-11',1,now(),now()),
(10,'zhaomin','123456','赵敏',2,'10.jpg',1,'2013-09-05',1,now(),now()),
(11,'luzhangke','123456','鹿杖客',1,'11.jpg',1,'2007-02-01',1,now(),now()),
(12,'hebiweng','123456','鹤笔翁',1,'12.jpg',1,'2008-08-18',1,now(),now()),
(13,'fangdongbai','123456','方东白',1,'13.jpg',2,'2012-11-01',2,now(),now()),
(14,'zhangsanfeng','123456','张三丰',1,'14.jpg',2,'2002-08-01',2,now(),now()),
(15,'yulianzhou','123456','俞莲舟',1,'15.jpg',2,'2011-05-01',2,now(),now()),
(16,'songyuanqiao','123456','宋远桥',1,'16.jpg',2,'2010-01-01',2,now(),now()),
(17,'chenyouliang','123456','陈友谅',1,'17.jpg',NULL,'2015-03-21',NULL,now(),now());
-- 一对一: 用户 与 身份证
create table tb_user(
id int unsigned  primary key auto_increment comment 'ID',
name varchar(10) not null comment '姓名',
gender tinyint unsigned not null comment '性别, 1 男  2 女',
phone char(11) comment '手机号',
degree varchar(10) comment '学历'
) comment '用户信息表';
insert into tb_user values (1,'白眉鹰王',1,'18812340001','初中'),(2,'青翼蝠王',1,'18812340002','大专'),(3,'金毛狮王',1,'18812340003','初中'),(4,'紫衫龙王',2,'18812340004','硕士');
create table tb_user_card(
id int unsigned  primary key auto_increment comment 'ID',
nationality varchar(10) not null comment '民族',
birthday date not null comment '生日',
idcard char(18) not null comment '身份证号',
issued varchar(20) not null comment '签发机关',
expire_begin date not null comment '有效期限-开始',
expire_end date comment '有效期限-结束',
user_id int unsigned not null unique comment '用户ID',
constraint fk_user_id foreign key (user_id) references tb_user(id)
) comment '用户信息表';
insert into tb_user_card values (1,'汉','1960-11-06','100000100000100001','朝阳区公安局','2000-06-10',null,1),
(2,'汉','1971-11-06','100000100000100002','静安区公安局','2005-06-10','2025-06-10',2),
(3,'汉','1963-11-06','100000100000100003','昌平区公安局','2006-06-10',null,3),
(4,'回','1980-11-06','100000100000100004','海淀区公安局','2008-06-10','2028-06-10',4);
--  多对多: 学生 与 课程
create table tb_student(
id int auto_increment primary key comment '主键ID',
name varchar(10) comment '姓名',
no varchar(10) comment '学号'
) comment '学生表';
insert into tb_student(name, no) values ('黛绮丝', '2000100101'),('谢逊', '2000100102'),('殷天正', '2000100103'),('韦一笑', '2000100104');
create table tb_course(
id int auto_increment primary key comment '主键ID',
name varchar(10) comment '课程名称'
) comment '课程表';
insert into tb_course (name) values ('Java'), ('PHP'), ('MySQL') , ('Hadoop');
create table tb_student_course(
id int auto_increment comment '主键' primary key,
student_id int not null comment '学生ID',
course_id  int not null comment '课程ID',
constraint fk_courseid foreign key (course_id) references tb_course (id),
constraint fk_studentid foreign key (student_id) references tb_student (id)
)comment '学生课程中间表';
insert into tb_student_course(student_id, course_id) values (1,1),(1,2),(1,3),(2,2),(2,3),(3,4);
-- 案例
-- 1. 分类表category
-- 2. 菜品表 dish
-- 3. 套餐表 setmeal
-- 4. 套餐菜品关系表 setmeal_dish
-- 分类表
create table category(
id int unsigned primary key auto_increment comment '主键ID',
name varchar(20) not null unique comment '分类名称',
type tinyint unsigned not null comment '类型 1 菜品分类 2 套餐分类',
sort tinyint unsigned not null comment '顺序',
status tinyint unsigned not null default 0 comment '状态 0 禁用，1 启用',
create_time datetime not null comment '创建时间',
update_time datetime not null comment '更新时间'
) comment '分类表' ;
-- 菜品表
create table dish(
id int unsigned primary key auto_increment comment '主键ID',
name varchar(20) not null unique comment '菜品名称',
category_id int unsigned not null comment '菜品分类ID',
price decimal(8, 2) not null comment '菜品价格',
image varchar(300) not null comment '菜品图片',
description varchar(200) comment '描述信息',
status tinyint unsigned not null default 0 comment '状态, 0 停售 1 起售',
create_time datetime not null comment '创建时间',
update_time datetime not null comment '更新时间'
) comment '菜品表';
-- 套餐表
create table setmeal(
id int unsigned primary key auto_increment comment '主键ID',
name varchar(20) not null unique comment '套餐名称',
category_id int unsigned not null comment '分类id',
price decimal(8, 2) not null comment '套餐价格',
image varchar(300) not null comment '图片',
description varchar(200) comment '描述信息',
status tinyint unsigned not null default 0 comment '状态 0 停售 1 起售',
create_time datetime not null comment '创建时间',
update_time datetime not null comment '更新时间'
)comment '套餐' ;
-- 套餐菜品关联表
create table setmeal_dish(
id int unsigned primary key auto_increment comment '主键ID',
setmeal_id int unsigned not null comment '套餐id ',
dish_id int unsigned not null comment '菜品id',
copies tinyint unsigned not null comment '份数'
)comment '套餐菜品关系';