what is the considered to be the best database model for simple inventory tracking?
- product type X is purchased and sold,
- product type Y is purchased and sold
- what is the current stock level of product X (total purchased - total sold)
- a running (ie daily) balance of stock purchased, stock sold, current balance etc
- one table with a field for Quantity and a field for transaction type (and convert qty sold to negative amounts)
- one table with separate fields for Qty_purchased and Qty_sold
- two tables - one purchased and one for sold