Is there a different way to open a cursor for a ref cursor procedure?

Question

hello everybody
i have two cursors, cur_a and cur_b, declared somewhere else in my application.
These two cursors have the same fields, in the same order, and i have to treat both in the same way. So i wrote a routine that gets as input a ref cursor based on the cur_a rowtype, and i am trying to use this routine for both.
The problem is that i am not able to open outside the routine the cursor in a different way than usual...
the common method is :
declare curs ref cursor ...
begin
open curs for (select *...)
end;
instead i would like to obtain something different
declare curs ref cursor ...
begin
open curs for cur_a
end;

Answer 1

hi
thanks for answering
i wanted just to give a better idea, anyway you were near to get it.
the only difference is that the two cursors are not written in dynamic sql, just like strings, but are real cursors.
anyway, this is the version of the package i need, but i am not able to compile
(your original code is commented and immediately below there is my code)
CREATE OR REPLACE PACKAGE BODY mytest
IS
--cur_a VARCHAR2(200) := 'SELECT dummy FROM DUAL';
CURSOR cur_a
IS
SELECT dummy
FROM DUAL;
--cur_b VARCHAR2(200) := 'SELECT ''fred'' FROM DUAL';
CURSOR cur_b
IS
SELECT 'fred' fred
FROM DUAL;
TYPE t_cur_a IS REF CURSOR
RETURN cur_a%ROWTYPE
--PROCEDURE routine_a_b (p_cur SYS_REFCURSOR) IS
PROCEDURE routine_a_b (p_cur t_cur_a)
IS
v_x VARCHAR2 (10);
BEGIN
LOOP
FETCH p_cur
INTO v_x;
EXIT WHEN p_cur%NOTFOUND;
DBMS_OUTPUT.put_line (v_x);
END LOOP;
END;
PROCEDURE doit
IS
--v_curs SYS_REFCURSOR;
v_curs t_cur_a;
BEGIN
NULL;
-- open v_curs FOR cur_a;
OPEN v_curs FOR cur_a;
routine_a_b (v_curs);
CLOSE v_curs;
-- open v_curs FOR cur_b;
-- routine_a_b(v_curs);
-- close v_curs;
END;
END;
the error is:
cursor 'V_CURS' cannot be used in dynamic SQL OPEN statement
i did read that if use weak ref cursor, it could work, so i declare the ref cursor type in this way:
TYPE t_cur_a IS REF CURSOR;
instead than
TYPE t_cur_a IS REF CURSOR
RETURN cur_a%ROWTYPE
what i get is another error (in the open cursor command)
PLS-00382: expression is of wrong type....
but if i replace
OPEN v_curs FOR cur_a;
with
OPEN v_curs for select dummy from dual;
it works... but i already knew it.. :-)
anyway, i used a work around to resolve it, so it's just philosophy