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Data Modeling Made Simple with ER/Studio Data Architect by Steve Hoberman

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An entity represents a collection of information about something that the business deems important and worthy of capture. A noun or noun phrase identifies a specific entity. An entity fits into one of six categorieswho, what, when, where, why, or how. Table 4.1 contains a definition of each of these entity categories along with examples.

Table 4.1 Definitions and examples of entity categories

Category

Definition

Examples

Who

Person or organization of interest to the enterprise. That is, Who is important to the business? Often a who is associated with a role such as Customer or Vendor.

Employee, Patient, Player, Suspect, Customer, Vendor, Student, Passenger, Competitor, Author

What

Product or service of interest to ...

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