unique_pk_fk.sql

简单的sql语句 数据与汇总。 高手多多指点。

select * from suppliers
go

alter table suppliers
add constraint u_companyname unique(companyname)
go

alter table customers
add 
constraint pk_customers 
primary key nonclustered (customerid)
go

alter table orders
add constraint fk_orders_customers
foreign key (customerid)
references customers(customerid)
go