constraint student_id_FK foreign key(student_id) references student(id)
);
一对一的对象的数据库设计
create table person
(
id int primary key,
name varchar(40)
);
create table idcard
(
city varchar(40),
constraint id_FK foreign key(id) references person(id)
);
自连接的表
create table person
(
id int primary key,
name varchar(40),
parent_id int,
constraint parent_id_FK foreign key(parent_id) references person(id)
);