use my_foreign;
create table myforeign2(
id int primary key auto_increment,
name varchar(20) not null,
c_id int,
foreign key(c_id) references my_class.myclass(id) on delete set null on update cascade
);
use my_class;
update myclass set id =4 where id = 3;
select * from myclass;
use my_foreign;
select * from myforeign2;
查询出来的结果并没有随之更新
