SQL & PL/SQL

Hi Experts,

I am on Oracle 11.2.0.2 on Linux. I have a task to generate all possible combinations of five digits (1 to 5) and each digit can be used only once. I wrote the code as below but I wonder if this is optimum - or if it can be improved on. i will be thankful for your commens about it:

DECLARE
BEGIN
   FOR i IN 1 .. 5
   LOOP
      FOR j IN 1 .. 5
      LOOP
         IF i = j
         THEN
            CONTINUE;
         ELSE
            NULL;
         END IF;
         FOR k IN 1 .. 5
         LOOP
            IF (j = k OR i = k)
            THEN
               CONTINUE;
            ELSE
               NULL;
            END IF;
            FOR l IN 1 .. 5
            LOOP
               IF (k = l OR i = l OR j = l)
               THEN
                  CONTINUE;
               ELSE
                  NULL;
               END IF;

               FOR m IN 1 .. 5
               LOOP
                  IF (l = m OR i = m OR j = m OR k = m)
                  THEN
                     CONTINUE;
                  ELSE
                     NULL;
                  END IF;
                  DBMS_OUTPUT.put_line (
                     i || ' ' || j || ' ' || k || ' ' || l || ' ' || m);
               END LOOP;
            END LOOP;
         END LOOP;
      END LOOP;
   END LOOP;
END;
/

Thnaks,

OrauserN