杨勇.txt

关于oracle和sql的书籍和ppt教程,非常好,本人珍藏品

create table merchandise_yang--商品表
(
    id number(9) primary key,
    sort_id number(9),
    name varchar2(20) not null unique,
    made_nation varchar2(20) check(made_nation in('美国','中国','法国','英国','日本')),
    foreign key(sort_id) references sort_yang
);

create table sort_yang--种类表
(
    sort_id number(9) primary key,
    sort_name varchar2(20) check(sort_name in('日用品','药品','食品','床上用品')),
    amount number(9) not null
);
/*insert into sort_yang values(200,'日用品',1000);
insert into merchandise_yang values (100,200,'牙膏','中国');
update merchandise_yang set name='牙刷' where name='牙膏';
delete from merchandise_yang where name='牙刷';*/

alter table merchandise_yang add (amount number(9)); 
alter table merchandise_yang modify(amount number(4));
alter table merchandise_yang drop (amount);