appraoch to a design

Going to create a stand alone application where users can view and update the data here via weekly to monthly upload from the production side. This is a one way transfer, we're not feeding back the data, just updating, allowing corrections, to the data uploaded, independent of the production system.

So, the user requires the ability to make changes to the data, and this is true for most and perhaps all fields.

How do we avoid overwriting the data that has been changed with each refresh?

     Keep 'parallel' columns for each field that are
     populated on the first upload, and modifiable
     by the users in the form?

    'Mark' the records which have been changed or modified,
     and not allow an overwrite for specific columns?

Or is there some other approach you might recommend?

Thanks

--
C   r   a   i   g   e   r   s
A tech once calmed a man who was enraged because "his computer had told him
he was bad and an invalid." The tech patiently explained that the computer's
"bad command" and "invalid" responses shouldn't be taken personally.