open c1:
loop
  fetch c1 into something;
  exit when c1%notfound;
  open c2;
  loop
    fetch c2 into something_else;
    exit when c2%notfound;
    -- do something
  end loop;
  close c2;
end loop;
close c1;

for r1 in c1 loop
  for r2 in c2 loop
    -- do something
  end loop;
end loop;