Select and function with no_data_found

Question

Hi,
I came across this today (I remembered reading about it somewhere).
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
SQL> create function rahul_f return varchar2 as
2 begin
3 raise no_data_found;
4 end rahul_f;
5 /
Function created.
SQL> select rahul_f from dual;
RAHUL_F
SQL> declare
2 i varchar2(1);
3 begin
4 i := rahul_f;
5 end;
6 /
declare
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at "XX.RAHUL_F", line 3
ORA-06512: at line 4
SQL>
So, I know this has something to do with 'no_data_found' mentioned here:
http://download.oracle.com/docs/cd/B19306_01/appdev.102/b14261/errors.htm#LNPLS00703
'Because this exception is used internally by some SQL functions to signal completion, you should not rely on this exception being propagated if you raise it within a function that is called as part of a query.'
Anybody have any link on explaining this part more? I looked around but, couldn't find any discussions on this.

Answer 1

I had same experience few days back.
First I dont think you need the funtion to call the exception.
You can directly implement your code in the EXCEPTION block, if theres a no_data_found excpetion.
This is my code..
PROCEDURE modify_req_det(
detail_id_in IN req_details.detail_id%TYPE,
type_id_in IN req_details.req_type_id%TYPE,
value_in IN VARCHAR2,
parent_in IN req_details.parent%TYPE,
sortorder_in IN req_details.sort_order%TYPE,
groupid_in IN req_details.group_id%TYPE,
errormsg OUT NOCOPY VARCHAR2) AS
BEGIN
SELECT DISTINCT lookup, col_name
INTO v_lookup, v_colname
FROM req_type t, req_details d
WHERE parent = parent_in
AND t.req_type_id = d.req_type_id;
EXCEPTION
WHEN no_data_found THEN
UPDATE req_details SET
req_type_id = type_id_in,
value_id = v_valueId,
parent = parent_in,
sort_order = sortorder_in,
group_id = groupid_in
WHERE detail_id = detail_id_in;
END modify_req_det;