Building a Data Model - High-Performance Web Databases: Design, Development, and Deployment - page 212

Exhibit 14-1. A data model for Ron's real estate business.

Attributes

More formally, an attribute is a fact or nondecomposable (atomic) piece
of information describing an entity. Nondecomposable means that an
attribute represents the smallest unit of information that will be referenced
at one time.

For example, notice that a renter address is represented as one attribute
(ADDRESS), but a property address is represented as two attributes
(STREET-ADDRESS and TOWN-STATE-ADDRESS). This design enables the
user to easily list all properties in a particular town and state; listing only
those renters in a particular town and state may be more difficult.

A particular entity occurrence can be identified by the values of its
attributes. For example, renter Harry Smith can be distinguished from
renter Josephine Morgan based on values of their attributes as illustrated