sql server ¶¨ÒåÖ÷¼ü

drop table father;
create table father(
 id int identity(1,1) primary key,
 name varchar(20) not null,
 age int not null
  
)
drop table mother;
create table mother(
 id int identity(1,1),
 name varchar(20) not null,
 age int not null,
 husband int not null
)
alter table mother
  add constraint FK_ID foreign key(husband) references father(id)
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drop table father;
create table father(
 id int identity(1,1),   (䶨Òå primary key)
 name varchar(20) not null,
 age int not null
)
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ÔÚ±»ÒýÓñí 'father' ÖÐûÓÐÓëÍâ¼ü 'FK_ID' µÄÒýÓÃÁеÄÁбíÆ¥ÅäµÄÖ÷¼ü»òºòÑ¡¼ü