Mutating Error problem using audit trigger for UPDATE

Question

I need to add 4 columns to all of my tables named:
INSERT_BY
INSERT_DATA
UPDATE_BY
UPDATE_DATE
I intend these to act as "inserted" and "last updated" audit trails within the table, as opposed to creating a new table and storing the audit information there. The insert columns appear to be easy, as I can just use a DEFAULT clause within the definition of the table. However when I attempted to write a (my first) trigger then I run into problems with mutating tables. Presumebly because I am attempting to change the table while the trigger is referencing it.
create or replace trigger test_audit
after update on dictionary
begin
update dictionary
set update_by = user, update_date = sysdate
where entity_id = :old.entity_id;
end;
I thought I could maybe get around this by calling a procedure from inside the trigger. Something like:
create or replace procedure test_audit(vColumn in varchar2, vData in varchar2, vTable in varchar2) is
-- vTable is table name
-- vColumn is PK of table
-- vData is value of PK in current row
begin
update vTable
set update_by = user, update_date = sysdate
where vColumn = vData;
commit;
end test_audit;
However I cannot use variable for table names. Will this mean I have to create a procedure for each table/trigger? Is there a way to reference the table name as a variable and keep this a generic procedure? Or is there an easier way to record the auditing UPDATE information for each changed row within the original table?
Many thanks in advance......

Answer 1

Will
this mean I have to create a procedure for each
table/trigger? I think you've answered that question already.
Is there a way to reference the table
name as a variable and keep this a generic procedure?Not that I'm aware of.
Or is there an easier way to record the auditing
UPDATE information for each changed row within the
original table?Well, there's the AUDIT feature.
C.