Progress
Database Design
Guide
Data Analysis
The first step in the database design cycle is to define the data requirements for your business. Answering these questions can help get you started:
- What types of information does my business currently use? What types of information does my business need?
- What kind of information do I want from this system? What kind of reports do I want to generate?
- What will I do with this information?
- What kind of data control and security does this system require?
- Where is expansion most likely?
To answer some of these questions, list all the data you intend to input and modify in your database, as well as all the expected outputs. For example, some of the requirements a retail store might include are the ability to:
- Input data for customers, orders, and inventory items
- Add, update, and delete rows
- Sort all customers’ addresses by zip code
- List alphabetically all the customers with outstanding balances of over $1,000
- List the total year-to-date sales and unpaid balances of all the customers in a specific region
- List all orders for a specific item (for example, ski boots)
- List all items in inventory that have less than 200 units, and automatically generate a reorder report
- List the amount of overhead for each item in inventory
- Track customer information so you that have a current listing of customer accounts and balances
- Track customer orders. Print customer orders and billing information for customers and the accounting department
- Track inventory so you know which materials are in stock, which you need to order, where they are kept, and how much of your assets are tied up with inventory
- Track customers’ returns on items so you know which items to discontinue or which suppliers to notify
Tables are generally grouped into three types — kernels, associations, and characteristics.
- Kernels are tables that are independent entities. They often represent or model things that exist in the real world. Some examples are: customers, vendors, employees, parts, goods, and equipment.
- Associations are talbes that represent a relationship among entities. For examples, an order represents an association between a customer and goods.
- Characteritics are tables whose purpose is to qulify or describe some other entity. These tables have no meaning in and of themselves, only in relation to the entity they describe. For example, order-lines might describe orders; without an order, an order-line is useless.
The process of identifying the goals of the business, interviewing, and gathering information from the different sources who are going to use the database is a time-consuming but essential process. With the information in hand, you are now ready to define your tables and columns.
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