Can any one answer this?

Question

All,
Can we have any limit for using nested loop in PL/SQL?
Regards
ND

Answer 1

user8900449 wrote:
The recurssion no doubt is elegant but the only problem arises when you are doing some sql or dml inside it.
Because it will end up opening as many cursors as your recursion revolves around.That depends on the scope of the cursor - whether it remains open for the duration of the procedure's lifetime, or whether it is closed before recursion occurs.
Simple (and ugly) example using implicit cursors (cursor is created and destroyed before the recursive call is made in the current active code unit), thus a single open cursor exist (per call) for the lifespan of the entire recursive call.
SQL> create or replace procedure Nest( levelNo number ) is
  2          i       integer;
  3  begin
  4          if levelNo > 0 then
  5                  select levelNo-1 into i from dual;
  6                  Nest( i );
  7          end if;
  8  end;
  9  /
Procedure created.
SQL>
SQL> exec Nest(1000000)
PL/SQL procedure successfully completed.
So be careful in recursion along with sql operation inside it.Agreed. But why would one want to use open SQL cursors in recursion? (i.e. each recursion creating a cursor with scope that spans the recursive call)
There are nested loop joins (courtesy of the CBO), hierarchical query support and so on. Using PL to solve a SQL problem (like doing manual nested loops in PL) is always a problem - not just an issue with PL recursion.