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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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