create table A(id int not null primary key) engine=innodb;
create table B(id int not null auto_increment primary key, f1 int not null, foreign key(f1) references A(id) on delete cascade) engine=innodb;
create table C(id int not null auto_increment primary key, f1 int not null, foreign key(f1) references B(id) on delete cascade) engine=innodb;
insert into A values(1), (2);
DELETE FROM A where id = 1;
DELETE FROM C where f1 = 2;
DELETE FROM A where id = 1;
DROP TABLE C;
DROP TABLE B;
DROP TABLE A;
