MySQL學習(二)——MySQL多表
阿新 • • 發佈:2017-11-30
tab total for limit ima ins 服飾 nbsp rod
分頁操作:使用limit(參數1,參數2)
起始位置(參數1)=(第幾頁-1)*每頁顯示的條數(參數2)
1.分類表
create table category(
cid varchar(32) primary key,
cname varchar(100)
);
2.商品表
create table product(
pid varchar(32) primary key,
pname varchar(40),
price double,
category_id varchar(32)
);
alter table product add foreign key(category_id) references category(cid);
3.添加外鍵列
alter table product add category_id varchar(32);
4.添加約束
alter table product add constraint product_fk foreign key(category_id) references category(cid);
5.訂單表
create table orders(
oid varchar(32) primary key,
totalprice double
);
6.訂單項表
create table orderitem(
oid varchar(50),
pid varchar(50)
);
7.聯合主鍵
alter table orderitem add primary key(oid,pid);
8.訂單表和訂單項表的主外鍵關系
alter table orderitem add constraint orderitem_orders_fk foreign key(oid) references orders(oid);
9.商品表和訂單項表的主外鍵關系
alter table orderitem add constraint orderitem_product_fk foreign key(pid) references product(pid);
insert into category(cid,cname) values(‘c001‘,‘家電‘);
insert into category(cid,cname) values(‘c002‘,‘服飾‘);
insert into category(cid,cname) values(‘c003‘,‘化妝品‘);
insert into product(pid,pname,price,category_id) values(‘p001‘,‘聯想‘,‘5000‘,‘c001‘);
insert into product(pid,pname,price,category_id) values(‘p002‘,‘海爾‘,‘5000‘,‘c001‘);
insert into product(pid,pname,price,category_id) values(‘p003‘,‘雷神‘,‘5000‘,‘c001‘);
insert into product(pid,pname,price,category_id) values(‘p004‘,‘JACK JONES‘,‘800‘,‘c002‘);
insert into product(pid,pname,price,category_id) values(‘p005‘,‘真維斯‘,‘200‘,‘c002‘);
insert into product(pid,pname,price,category_id) values(‘p006‘,‘花花公子‘,‘440‘,‘c002‘);
insert into product(pid,pname,price,category_id) values(‘p007‘,‘勁霸‘,‘2000‘,‘c002‘);
insert into product(pid,pname,price,category_id) values(‘p008‘,‘香奈兒‘,‘800‘,‘c003‘);
insert into product(pid,pname,price,category_id) values(‘p009‘,‘相宜本草‘,‘200‘,‘c003‘);
聲明外鍵約束
1.從orderitem到product的關系
alter table orderitem add foreign key(pid) references product(pid);
1.1 刪除外鍵約束
alter table 從表 drop foreign key 外鍵名稱
2.從orderitem到orders的關系
MySQL學習(二)——MySQL多表