TABLE FUNCTION OR CAST WITH TABLE FUNCTION

Question

Consider following scenario:
I've a function which returns nested table of employees.
I am calling this function in some other procedure and building a query dynamically.
Sample code looks like
CREATE OR REPLACE  PROCEDURE TEST_PROC( P_EMP_ID   IN   NUMBER,
                                        O_EMP_LIST OUT  SYS_REFCURSOR) IS
v_tbl_emp_id       tbl_emp_id;
begin
v_tbl_emp_id :=  fn_get_usr_list (P_EMP_ID);--fetches employee id  reporting to given emp id
v_select_clause :=
         'SELECT EMP_NO,EMP_NAME,DEPT_NO';
v_from_clause := ' FROM EMP';
v_where_clause1 :=
            ' WHERE emp_no IN (
                      SELECT  COLUMN_VALUE
                                 FROM TABLE
                                         (CAST
                                             (:v_tbl_emp_id AS tbl_emp_id
--AND I AM APPENDING AND CLAUSES BASED ON VARIOUS CONDITION
v_qry :=     v_select_clause  || v_from_clause|| v_where_clause1;
OPEN O_EMP_LIST FOR v_qry USING v_tbl_emp_id;
END TEST_PROC;I CAN REWRITE THE SAME CODE AS
CREATE OR REPLACE  PROCEDURE TEST_PROC( P_EMP_ID   IN   NUMBER,
                                        O_EMP_LIST OUT  SYS_REFCURSOR) IS
begin
v_select_clause :=
         'SELECT EMP_NO,EMP_NAME,DEPT_NO';
v_from_clause := ' FROM EMP';
v_where_clause1 :=
            ' WHERE emp_no IN (
                      SELECT  COLUMN_VALUE
                                 FROM TABLE(fn_get_usr_list (:P_EMP_ID)))';
--AND I AM APPENDING AND CLAUSES BASED ON VARIOUS CONDITION
v_qry :=     v_select_clause  || v_from_clause|| v_where_clause1;
OPEN O_EMP_LIST FOR v_qry  USING P_EMP_ID;
END TEST_PROC;Now I would like to know which one performs better
USING TABLE ALONE OR USING CAST ALONG WITH THE TABLE FUNCTION?
AND PLEASE HELP ME ON FORMATTING CODE.
I've added tags still its not formatting!!
Thanks,
NM
Edited by: user10862473 on Apr 11, 2011 12:14 AM
Edited by: BluShadow on 11-Apr-2011 09:13
fixed {noformat}{noformat} tags

Answer 1

To be sure which is better you will have to test them both. You can use either AUTOTRACE or Oracle trace (tkprof) to get run metrics - system resources used when running both versions of the query. AUTOTRACE won't provide CPU information, but if you can find the qieries in (G)V$SQL you can find it there. Oracle trace is more effort but should provide more metrics. I could do it if I have privileges :(..
All I can do is check the time taken by the both procedures using set timing on, which gives same result for both.
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.07Thanks,
NM