A subject is a person, place, thing, event, or other real-world item that matters to a database design. During requirements gathering, identifying subjects helps reveal what the database must represent. Record each subject alongside its characteristics—the features that describe it—and the relationships among subjects. section 3.15
Use subjects as a practical starting point for database design:
- Identify the people, places, things, and events relevant to the organization. section 3.15
- List the characteristics that describe each subject. section 3.15
- Note how subjects relate to one another. section 3.15
- Turn each subject into an entity and each characteristic into an attribute, then apply consistent names. section 4.2
From subject to entity
Suppose requirements identify an employee as a relevant subject. The employee becomes an entity, while features such as a name become attributes. The design then gives the entity and attributes consistent names, such as employee and first_name, rather than switching naming styles. section 4.2
