In Richard's classes Sale Tax Rate is stored in up to 4 places:
    - Customer Table (each customer can have their own rate)
    - Product Table (each product can have its own rate)
    - Order Table (Rate for entire order - previous orders unaffected by change)
    - Order Detail Table (Rate for each line item - detail items on previous orders unaffected by change)

Please be more specific. See Rule #2. Show your table in design view as well as the query that does the calculations.

Hi Ben, In Richard's Invoicing video Extended Cut he chooses products (to prevent the very issue that you have encountered). Watch the video to see how he selects products for the invoice.  John

Like the other guys have said, you have to copy the rate to the order itself. This way older orders aren't affected.

Access Expert 22
Invoicing - extended cut

This concept applies to many types of historical data based on transaction processing. Always consider how future events might affect your data. Not just sales tax; how about the address an order was shipped to?

After the customer moves, and you change their address (hopefully not in the customer record itself) how will you know where it was shipped? Did you put the full address in the order? It works, but equally bad design. You need an address table and you only store the ID in the order, invoice, customer, etc. tables. Likewise, you do have a tax table right? You create a new tax record when the rate changes, you just don't change the tax in the existing record.

The above image is what I consider a well-designed address form. A family of n people can share this address. N families can live in the building. One can easily view or share mapping coordinates. When a family moves, you do not change this address record. You use a new one. Why? Well, the building hasn't moved, has it?

Since Richard likes to share histories, this particular place (my college pad) is where Advanced Data Business Systems (ADBS) started 44 years ago. I had graduated from university, was at my third job, and at night was designing my rapid application development (RAD) software. On paper, since IBM PCs weren't out yet.