34,571
社区成员
发帖
与我相关
我的任务
分享
create table country (id int identity, code char(4) not null, name varchar(40) not null);
create unique index ix_country_code on country(code);
go
insert into country(code, name) values('0001','China');
go
create table city (id int identity, code char(8) not null, name varchar(40) not null);
create unique index ix_city_code on city(code);
go
insert into city (code,name) values('00010001','Beijin');
go
create table person
(id int identity, code char(12) not null, name varchar(40) not null,
country_code char(4) references country(code),
city_code char(8) references city(code));
create unique index ix_person_code on person(code);
go
insert into person (code, name,country_code,city_code)
values ('000100010001','Hu','0001',null);
go
select * from person;
/*
1 000100010001 Hu 0001 null
*/
update person set city_code='00010001' where id=1;
select * from person;
/*
1 000100010001 Hu 0001 00010001
*/
drop table person,country,city;
go
create table country (id int identity, code char(4) not null, name varchar(40) not null);
create unique index ix_country_code on country(code);
create table city (id int identity, code char(8) not null, name varchar(40) not null);
create unique index ix_city_code on city(code);
create table person
(id int identity, code char(12) not null, name varchar(40) not null,
country_code char(4) references country(code),
city_code char(8) references city(code));
create unique index ix_person_code on person(code);