Question : tell if an item value has changed

Is there a way to tell if an item in particular in a record has been changed in the pre-update trigger?  

I am looking for a way to do something like this :
if this_item = 'CHANGED' then
update statement;
end if;

Answer : tell if an item value has changed

check if some
can execute the following  in toad
alter session set NLS_NUMERIC_CHARACTERS='.,'
/
and repeat
select to_number('123.45') from dual;

in your sqlpus you mention to_char instead of to_number : that is a different query
behaviour can be different for the same query as
sqlplus looks for a login.sql prior to connect and in that file settings as above can be changed

check your registry for NLS_SETTINGS that might be changed by your XE installation
for example
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\ORACLE\KEY_XE
and check the same for toad