创建表约束

主键约束

create table Items(ItemNo number(2) constraint PK_Items primary key,

ItemName varchar2(20) not null);

外键约束

create table business(

busino number(2) constraint pk_business primary key,

businessname varchar(32) not null,

itemno number(2) ,

constraint fk_business foreign key(itemno) references Items(ItemNo),

starttime date

);