For-in-loop produces "ORA-06502: PL/SQL: numeric or value error"

Question

Why i'm getting error "ORA-06502: PL/SQL: numeric or value error" in below code.
create table bc (
  a number,
  b varchar2(10)
declare
  type t_bc_a is table of bc.a%type;
  type t_bc_b is table of bc.b%type;
  l_bc_a t_bc_a;
  l_bc_b t_bc_b;
begin
  dbms_output.put_line('1');
  select a, b bulk collect into l_bc_a, l_bc_b from bc;
   dbms_output.put_line('2');
   if l_bc_a is null then
     dbms_output.put_line('2.1');
   else
     dbms_output.put_line('2.2, l_bc_a.count=' || l_bc_a.count);
   end if;
  for i in l_bc_a.first .. l_bc_a.last loop
   dbms_output.put_line('3');
    dbms_output.put_line(l_bc_a(i) || ', ' || l_bc_b(i));
  end loop;
end;
1
2
2.2, l_bc_a.count=0
ORA-06502: PL/SQL: numeric or value error
*/Table "bc" is empty, and i expect for-loop to never do any cycle/step, but i get error. Why the error is there.

Answer 1

1006192 wrote:
I'm encountering this problem often...i'm new to pl/sql language.
Can i just say(hoping to make you guys think on it) that this is madness???
I mean, it's a wonderful language, but i really think a for loop should simply skip a empty collection, without need of a special care.Please don't drag up old threads.
It's not madness. The collection is not "empty" if it's null, it's "unknown", as a collection would have to be initialised to be empty. As it's null (unknown), Oracle cannot know what the start or end of the collection is, so it correctly flags this up as an error.