SQL> desc a;
 Name                                                  Null?    Type
 ----------------------------------------------------- -------- ------------------------------------
 ID                                                             LONG RAW

SQL> select count(*) from a;

  COUNT(*)
----------
         4

SQL> declare
  2  cursor c1 is select id from a;
  3  begin
  4  for mag in c1
  5  loop
  6     insert into a values (mag.id);
  7  end loop;
  8  commit;
  9  end;
 10  /

PL/SQL procedure successfully completed.

SQL> select count(*) from a;

  COUNT(*)
----------
         8