Identifying the information to store
To develop a system of tables for an application, begin by identifying all of the relevant information you need to manage—unnecessary data wastes disk space and distracts users from the task at hand.
You might start by looking at the order form you use day to day. Write down all the information you think you need, without attempting to organize it yet, as shown in the following example:
Products ordered
Customer name, address, phone number, credit standing
Order number
Shipping information, including when it was shipped
Products purchased
Purchase date and time
Salesperson taking the order
Customer signature
Special notes about the customer
Next, review this list to see what’s really relevant and what you can do without. For example, the name of the salesperson taking the order might not be important, or you might decide you don’t need to track the exact time of purchase.