Clob field not working in BEFORE INSERT trigger

Question

Hello, everyone. I am trying to create a before insert trigger for a table (10g). I would like to create a value for a table field based on the xml query from a clob field. The table looks like this:
SQL> desc lac_costing_upload
Name Type Nullable Default Comments
UPLOAD_ID NUMBER Y
EMP_NUM VARCHAR2(20)
UPLOAD_DATE DATE Y
YEAR_MONTH VARCHAR2(10) Y
UPLOAD_TEXT CLOB Y
The trigger code looks like this:
create or replace trigger lac_cst_upl_yr_month
before insert on lac_costing_upload
for each row
declare
l_month varchar2(20);
l_year varchar2(20);
l_error_msg varchar2(255);
begin
SELECT XMLTYPE (:old.upload_text).EXTRACT('Oracle_Extract/Year/text()').getstringval() Extr_Year
, XMLTYPE (:old.upload_text).EXTRACT('Oracle_Extract/Month/text()').getstringval() Extr_Month
into l_year
, l_month
FROM dual;
:new.year_month := l_year || '.'
|| substr(l_month, 1, 3)
exception
when others then
l_error_msg := substr(sqlerrm, 1, 10);
:new.year_month := l_error_msg;
end lac_cst_upl_yr_month;
Here is a sample insert statement:
insert into lac_costing_upload lcu values(2006, '008925', sysdate, null
, '<Oracle_Extract>' || chr(10)
|| ' <Emp_Num>05417</Emp_Num>' || chr(10)
|| ' <Emp_Name>Fitzgerald</Emp_Name>' || chr(10)
|| ' <Year>2007</Year>' || chr(10)
|| ' <Month>May</Month>' || chr(10)
|| ' <Vehicle>1330</Vehicle>' || chr(10)
|| '</Oracle_Extract>'
My hope was to see '2007.May' in the year_month field. However, I'm getting 'ORA-06502:' instead. It looks like the value of :old.upload_text is null in the trigger.
Can anyone tell me what I'm doing wrong?
Thanks for any help.
--Dave                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

That's probably a really dumb error, but I don't work much with triggers.
It's working now.
Thanks for your help.
--Dave