When to Denormalize a Database Design

Question

I know that normalization has been extensively discussed on Stack Overflow. I\'ve read many of the previous discussions. I\'ve got some additional questions though.

I

Answer 1

For #1

The invoice should be calculated from the sales and payments. If you do not have detailed sales data including price/product/discount/shipping/etc start there.

For #2

Writing an accounting system into the db from scratch is a big project. Make sure you have the accountants give you business rules so you can measure your systems accuracy. The last thing you want is the CFO step into the DBA meeting and announce the DB is overcharging the customer, even worse you are undercharging and driving the company out of business.

If you have SQL Server give the Adventure Works db a look. If you hate MS then look at Adventure Works and don't do it that way.