Help with Oracle Table Audit Trigger

Question

Hi Guys,
Need some help with the design of a trigger please. I have created one standard audit table where all sensitive data will be audited/inserted. The idea is to insert the column name and the old and new values here, dont want to maintain an audit table for each and every table there is, reporting would be a nightmare.
Trying to fetch all the column names from sys objects then looping through each and inserting the new and old values for them into the audit table. Everything else is fine apart from the actual :old and :new value inserts. The column name is coming from a variable in a cursor and this is where I seem to be failing.
Can anyone help please? What is the correct syntax to use?
CREATE OR REPLACE TRIGGER commission_update
    AFTER UPDATE
        ON commission
        FOR EACH ROW
DECLARE
        v_username varchar2(10);
          v_column varchar2(20);
          -- Get Table Columns
          cursor table_column is
                  select c.name
                  from  sys.col$ c, sys.obj$ t
                  where t.obj# = c.obj#
                  and   t.type# in (2, 3, 4) 
                  and   bitand(c.property, 32) = 0 /* not hidden column */
                  and t.name = 'COMMISSION';
    BEGIN
        -- Find username of person performing UPDATE into table
        SELECT user
     INTO v_username
        FROM dual;
          open table_column;
                loop
                      fetch table_column
                     into v_column;                    
                     EXIT WHEN table_column%NOTFOUND;
                             -- Insert record into audit_record
                         INSERT INTO audit_record
                              ( aud_code,
                                  aud_ban_code,
                                  aud_user,
                                  aud_table,
                              aud_column,
                               aud_old_val,
                               aud_new_val,
                               aud_date )
                            VALUES
                              ( xaudit_record.nextval,
                                  :old.com_ban_code,
                                  v_username,
                                  'COMMISSION',
                               v_column,
                               :old.v_column, /* problem here!!!!!!! */
                               :new.v_column, /* problem here!!!!!!! */
                               sysdate );
                end loop;
          close table_column;
    END;
/

Answer 1

What does auditing mean in the financial environment? "An audit is a professional, independent examination of a company's financial statements and accounting documents according to generally accepted accounting principles."
What does it mean in database terms? Surely, the basic definition would be the same, ito of a proper independent examination of changes in the database according to accepted principles?
And just how does a trigger live up to that? When it is fully dependent on being enabled for that transaction in order to examine it? It is trivial to disable a trigger, make changes, and re-enable it.
So what happens to your "auditing" then?
Do you really think that a trigger suffices as a means to audit changes in a table? And if so, what logic and reasoning do you use to discard Oracle's auditing features that are built into the core of the database?