用户购物（数据库）案例

用户表 (用户的ID,用户名,密码,手机) 

create table user(
	uid int primary key auto_increment,
  	username varchar(31),
  	password varchar(31),
  	phone  varchar(11)
);

insert into user values(1,zhangsan,123,13811118888);

订单表 (订单编号,总价,订单时间 ,地址,外键用户的ID)

 create table orders(
  	oid int primary key auto_increment,
    	sum int not null,
      otime timestamp,
    	address varchar(100),
    	uno int,
    	foreign key(uno) references user(uid)
  );
  insert into orders values(1,200,null,黑马前台旁边小黑屋,1);
  insert into orders values(2,250,null,黑马后台旁边1702,1);

商品表 (商品ID, 商品名称,商品价格,外键cno)

create table product(
	pid int primary key auto_increment,
  	pname varchar(10),
  	price double,
  	cno int,
  	foreign key(cno) references category(cid)
);

insert into product values(null,小米mix4,998,1);
insert into product values(null,锤子,2888,1);
insert into product values(null,阿迪王,99,2);
insert into product values(null,老村长,88,3);
insert into product values(null,劲酒,35,3);
insert into product values(null,小熊饼干,1,4);
insert into product values(null,卫龙辣条,1,5);
insert into product values(null,旺旺大饼,1,5);

订单项: 中间表(订单ID,商品ID,商品数量,订单项总价)

create table orderitem(
	ono int,
  	pno int,
  	foreign key(ono) references orders(oid),
  	foreign key(pno) references product(pid),
  	ocount int,
  	subsum double
);
--给1号订单添加商品 200块钱的商品
insert into orderitem values(1,7,100,100);
insert into orderitem values(1,8,101,100);

--给2号订单添加商品 250块钱的商品 ()
insert into orderitem values(2,5,1,35);
insert into orderitem values(2,3,3,99);

商品分类表(分类ID,分类名称,分类描述)

create table category(
	cid int primary key auto_increment,
  	cname varchar(15),
  	cdesc varchar(100)
);

insert into category values(null,手机数码,电子产品,黑马生产);
insert into category values(null,鞋靴箱包,江南皮鞋厂倾情打造);
insert into category values(null,香烟酒水,黄鹤楼,茅台,二锅头);
insert into category values(null,酸奶饼干,娃哈哈,蒙牛酸酸乳);
insert into category values(null,馋嘴零食,瓜子花生,八宝粥,辣条);

关系图：