With very few exceptions, you should NOT be storing calculated data in your
tables: it's a waste of space, it's slow (disc access time to retrieve
records is much longer than calculation time), and worst, it's likely to
lead to inconsistent data if the underlying value(s) change.
The standard approach is to do such calculation in a query (in a blank
field, enter "Total: [Commission]+[Salary]"), and base your forms/reports on
the query, rather than on the underlying table. Or, if you only need the
result displayed on a form/report (rather than being available to sort or
filter on, for example), just do as you are doing now.
"Dave - Need help with my form" <Dave - Need help with my