passing cursor values into another function - sql

Question

*i have a function which will delete the rows in the table for the given input id, the input is given to the function by another cursor_function.*
select * from t1;
id | col1
----+-------
1 | user1
2 | user2
3 | user3
4 | user4
5 | user5
(5 rows)
create or replace function del_t1(int) returns void as $$
declare
a alias for $1;
begin
delete from t1 where id = a;
return;
end;
$$language plpgsql;
create or replace function del_cur(ref refcursor) returns void as $$
declare
a int;
begin
open ref scroll for select id from t1 where id > 3 order by id desc;
fetch first from ref into a;
perform del_t1(a);
loop
a := 0;
fetch next from ref into a;
perform del_t1(a);
if (a=0) then
exit;
end if;
end loop;
end;
$$ language plpgsql;
when the function is executed,
postgres# select del_cur('t1');
it shows no error, no outputs, cursor just blinks, plz help me to solve this, this is small description of my big database tables, i need a cursor function which will pass its values one by one to another function.

Answer 1

In your example the function del_cur(refcursor) is declared to take a cursor. But you never actually use it inside the function - the construct makes no sense at all.
What you are trying to do should be much easier with the implicit cursor of a FOR loop:
CREATE OR REPLACE FUNCTION del_stuff()
RETURNS void AS
$BODY$
DECLARE
_a int;
BEGIN
FOR _a IN
SELECT id FROM t1 WHERE id > 3 ORDER BY id DESC
LOOP
DELETE FROM t1 WHERE id = _a;
-- do other stuff?
END LOOP;
END;
$BODY$ LANGUAGE plpgsql;
I don't understand the need to delete the rows one by one in descending order. Are triggers involved? Maybe the whole thing can be as simple as:
DELETE FROM t1 WHERE id > 3;