Computation after pressing button

Question

this one should be esay, just wanna know how to a computation after pressing a button
thx in advance

Answer 1

this exactly what i have, this is the computation
DECLARE
id_people NUMBER;
name VARCHAR(400);
id_mandal NUMBER;
CURSOR c1 IS SELECT id_people from reg_people where id_mandal=:SELECT_MANDAL;
BEGIN
OPEN c1;
LOOP
FETCH c1 INTO id_people;
EXIT WHEN c1%NOTFOUND;
insert into reg_registration values(null,id_people,to_char(:SELECT_DATE),'N');
END LOOP;
close c1;
END;
so when i press a tab to change the page, the page is submited again so , the computation runs again, why??