Business rules are a description of a policy, procedure or principal within a specific organization. Business rules define entities, attributes, relationships and constraints; all of which are building blocks of a solid database.

Entities are the people, places and things in an organization and from a database perspective are things about which data can be stored. The characteristics of the entities that the organization does business with are attributes. The relationship of the organization’s entities is learned through business rules, which determine how data will be related in the database, one to one, one to many or many to many. Constraints are part of the business rules and determine the restrictions on data. Constraints also protect data integrity.

I knew a DBA who created a database based on assumptions and not on careful documentation of the business rules. It was a failure because it did not deliver the information that the company needed. It was used for a short period and then abandoned as unworkable.

Understanding and following the business rules allows the database designer to build a database that accurately reflects the workings of the business and becomes a useful tool for the manipulation of data and delivery of reliable information to the organization. Let me know of your experiences with database design.