Return updated rows from a stored function - oracle

Question

Im trying to select some rows from a Table in ORACLE and at the same time update the selected rows state. I found a way to do so with a stored function and Cursors but I cant manage to return the rows after using the cursor to update. This is my code:
CREATE OR REPLACE FUNCTION FUNCTION_NAME
RETURN SYS_REFCURSOR
IS
l_return SYS_REFCURSOR;
CURSOR c_operations IS
SELECT * FROM TABLE1
WHERE STATUS != 'OK'
FOR UPDATE OF TABLE1.STATUS;
BEGIN
FOR r_operation IN c_operations
LOOP
UPDATE
TABLE1
SET
TABLE1.STATUS = 'OK'
WHERE
TABLE1.ID_TABLE1 = r_operation.ID_TABLE1;
END LOOP;
COMMIT;
-- Missing conversion from cursor to sys_refcursor
RETURN l_return;
END;
The update is working but Im still missing how to return the updated rows that are in the cursor (c_operations ).
Thank you.

Answer 1

I'm going to make some assumptions:
id_table1 is the primary key of the table, so your RBAR (*) update affects only one row
id_table1 is numeric
If these assumptions are wrong you will need to tweak the following code.
CREATE OR REPLACE FUNCTION FUNCTION_NAME
RETURN SYS_REFCURSOR
IS
l_return SYS_REFCURSOR;
l_id table1.id_table1%type;
l_upd_ids sys.odcinumberlist := new sys.odcinumberlist();
CURSOR c_operations IS
SELECT * FROM TABLE1
WHERE STATUS != 'OK'
FOR UPDATE OF TABLE1.STATUS;
BEGIN
FOR r_operation IN c_operations LOOP
UPDATE TABLE1
SET TABLE1.STATUS = 'OK'
WHERE TABLE1.ID_TABLE1 = r_operation.ID_TABLE1
returning TABLE1.ID_TABLE1 into l_id;
l_upd_ids.extend();
l_upd_ids(l_upd_ids.count()) := l_id;
END LOOP;
COMMIT;
open l_return for
select * from table(l_upd_ids);
RETURN l_return;
END;
The key points of the solution.
uses Oracle maintained collection (of number) sys.odcinumberlist to store the updated IDs;
uses RETURNING clause to capture the id_table1 value for the updated row;
stores the returned key in the collection;
uses a table() function to casrt the collection into a table which can be queried in the ref cursor.
This last point is why I chose to use sys.odcinumberlist rather than defining a collection in the procedure. It's a SQL type, so we can use it in SELECT statements.
(*) Row-by-agonizing-row. Updating single records in a PL/SQL loop is the slowest way of executing bulk updates, and normally constitutes an anti-pattern. A straightforward set-based UPDATE should suffice. However, you know your own situation so I'm going to leave that as it is.

Answer 2

It looks to me like you don't need the initial cursor, since you're changing the STATUS of every row which is not 'OK' to 'OK', so you can do this is a simple UPDATE statement. Then use an OPEN...FOR statement to return a cursor of all rows where STATUS is not 'OK', which shouldn't return anything because you've already changed all the status values to 'OK'. I suggest that you rewrite your procedure as:
CREATE OR REPLACE FUNCTION FUNCTION_NAME
RETURN SYS_REFCURSOR
IS
l_return SYS_REFCURSOR;
BEGIN
UPDATE TABLE1
SET STATUS = 'OK'
WHERE STATUS != 'OK';
COMMIT;
OPEN l_return FOR SELECT *
FROM TABLE1
WHERE STATUS != 'OK'
FOR UPDATE OF TABLE1.STATUS;
RETURN l_return;
END;

Answer 3

Instead of a loop to update how about a bulk update collecting the updated ids. Then a table function from those returned ids.
create type t_table1_id is
table of integer;
create or replace function set_table1_status_ok
return sys_refcursor
is
l_results_cursor sys_refcursor;
l_updated_ids t_table1_id;
begin
update table1
set status = 'Ok'
where status != 'Ok'
returning table1.id
bulk collect
into l_updated_ids;
open l_results_cursor for
select *
from table1
where id in (select * from table(l_updated_ids));
return l_results_cursor;
end set_table1_status_ok;
-- test
declare
updated_ids sys_refcursor;
l_this_rec table1%rowtype;
begin
updated_ids := set_table1_status_ok();
loop
fetch updated_ids into l_this_rec;
exit when updated_ids%notfound;
dbms_output.put_line ( l_this_rec.id || ' updated.');
end loop;
close updated_ids;
end ;