You also need an Invoice Header table and an Invoice Detail table. The
Header should carry the information about who the customer is, where it will
be shipped, the date of the order, etc. The Detail table should carry the
stock code, the number ordered, the number shipped, the unit price, etc.
One issue to consider is where the tax rate goes. If you are in an
environment where the tax rate will be the same for all items regardless of
what they are or where they are being shipped, then the Header file would be
appropriate. If some items are taxable and some or not, then the tax rate
should be in the Detail.
Some things that do not go in any table at any time:
The line item total price.
The total invoice price.
The line intem tax amount.
The total tax amount.
The number of items on back order.
(Note these are all calculated values and should not be stored in tables.)
