Auto Subtraction Problem!!!

[tajurrehman]

Dear All,



I have Access Database consist of 6 tables names (Purchase Detail, Purchase Entry, Product, Sale Detail, Sale Entry and Customer)
These tables have relations.
In the Invoice Subform there is detail of Customer called Using DLookup function. In the Detail of Subform i have attached the Sale Detail Table and set it to dataseet format. In the invoice i have called the fields from Product Table (ProductName and PhysicalStock) with this function when i select productname the physicalstock comes also. in this invoice i can add mutiple products to sale.

The main issue i am facing that how can i subtract Product in PhysicalStock while i am issuing an invoice.
i want that when i add quantity in sale inovice function should able to track and subtract Product Quantities.

Thanks to All.

[orange]

See this often referenced article from Allen Browne for info on Quantity on Hand.