>Hi,
> I am developing retail Point of Sales System. I have a question that, How should I manage stock. Should I keep my stock status base on invoice basis or summary basis
>
>Invoice Basis
>Every item from each invoice will be recorded in table which store the current item's qty. Therefore, item will be sold base on invoice or FIFO basis, all return, transfer, and etc have to refer to invoice no and supplier no.
>
>Summary
>One record per item.
>
>How would u design it in real world? Is FIFO here is very important? DO you think design it in invoice basis is too troublesim.complicated for user and also developers? What do you think about both method, or do you have other suggestions?

The main question you have to answer here is, "Am I reinventing the wheel?" There are literally hundreds of POS software systems out there, for almost every conceivable industry.