How to insert a note when a field is updated

Question

Hello! I have an employee table, which have a company_id field. When the employee is changing it's company_id, I'd like to notify this in the note field. How can I do this? I tried to use a before update trigger,
(if :NEW.company_id <> :OLD.company_id) then
insert into employee(notes)
values('...'); but it didn't work.
Does somebody have other suggestions?
I would appreciate a lot!

Answer 1

Vitaly,
Is wath you are doing not the functionality of a journal table. Normaly you create for this purpose a table named 'employees_jn' for inserting the old records.
But if you want to do it in the same table you can do it with:
create package emp_pck is
   company_id  number;
   first_name  varchar2(100);
   last_name   varchar2(100);
end;
create or replace trigger "Employees_bur"
BEFORE
update on "Employees"
for each row
begin
   if :NEW.company_id = :OLD.company_id
   then
      emp_pck.company_id   := null;
      emp_pck.first_name   := null;
      emp_pck.last_name    := null;
   else
      emp_pck.company_id   := :OLD.company_id;
      emp_pck.first_name   := :OLD.first_name;
      emp_pck.last_name    := :OLD.last_name;
   end if;
end;
create or replace trigger "Employees_bus"
BEFORE
update on "Employees"
begin
   if emp_pck.company_id   is not null
   or emp_pck.first_name   is not null
   or emp_pck.last_name   is not null
   then
      insert into employees(first_name,last_name,company_id,edit_date)
      values(emp_pck.first_name,emp_pck.last_name,emp_pck.company_id,SYSDATE);
   end if;
end;
/Fred.