On delete cascade

create table pt (
  a number primary key, 
  b varchar2(30)
);

create table ft (
  a references pt on delete cascade,
  c varchar2(30)
);


insert into pt values ('1','first');
insert into ft values ('1','eins');
insert into ft values ('1','one');
insert into ft values ('1','un');

insert into pt values ('2','second');
insert into ft values ('2','deux');
insert into ft values ('2','zwei');
insert into ft values ('2','two');

delete from pt where a =1;

select * from ft;

drop table ft;
drop table pt;