Question

数据库的设计

创建 "商品分类" 表(之前已经创建,无需再次创建)

create table goods_cates(
    id int unsigned primary key auto_increment not null,
    name varchar(40) not null
);

创建 "商品品牌" 表(之前已经创建,无需再次创建)

create table goods_brands (
    id int unsigned primary key auto_increment not null,
    name varchar(40) not null
);

创建 "商品" 表(之前已经创建,无需再次创建)

create table goods(
    id int unsigned primary key auto_increment not null,
    name varchar(40) default '',
    price decimal(5,2),
    cate_id int unsigned,
    brand_id int unsigned,
    is_show bit default 1,
    is_saleoff bit default 0,
    foreign key(cate_id) references goods_cates(id),
    foreign key(brand_id) references goods_brands(id)
);

创建 "顾客" 表

create table customer(
    id int unsigned auto_increment primary key not null,
    name varchar(30) not null,
    addr varchar(100),
    tel varchar(11) not null
);

创建 "订单" 表

create table orders(
    id int unsigned auto_increment primary key not null,
    order_date_time datetime not null,
    customer_id int unsigned,
    foreign key(customer_id) references customer(id)
);

创建 "订单详情" 表

create table order_detail(
    id int unsigned auto_increment primary key not null,
    order_id int unsigned not null,
    goods_id int unsigned not null,
    quantity tinyint unsigned not null,
    foreign key(order_id) references orders(id),
    foreign key(goods_id) references goods(id)
);

说明

• 以上创建表的顺序是有要求的,即如果goods表中的外键约束用的是goods_cates或者是goods_brands,那么就应该先创建这2个表,否则创建goods会失败
• 创建外键时,一定要注意类型要相同,否则失败