[AccessD] how to do this?

Well you can either store the Quantity on Hand or Calculate it
Here is an article that describes the pros and cons, This will affect 
your overall design.
Inventory Control: Quantity on Hand
http://members.iinet.net.au/~allenbrowne/AppInventory.html


pedro at plex.nl wrote:

>Hello Group,
>
>What is the best way to do the following routine?
>
>I have a form with a field: [ArticleNumber]. I am scanning a barcode and the Article Number is placed in the field. When the Article number is placed this number must be processed as Follows; (in the table behind the form is also a field: [Quantity]) the value of [Quantity] must be decreased with 1. When the amount of [Quantity] reaches a certain minimum a message box must appear.
>
>How can this been done.
>
>Thanks
>
>Pedro Janssen 
>
>
>  
>

-- 
Marty Connelly
Victoria, B.C.
Canada