O'Reilly logo

Analysis Patterns: Reusable Object Models by Martin Fowler

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

3. Observations and Measurements

Many computer systems record information about objects in the real world. This information finds its way into computer systems as records, attributes, objects, and various other representations. The typical route is to record a piece of information as an attribute to an object. For example, the fact that I weigh 185 pounds would be recorded in an attribute of a person type. This chapter examines how this approach fails and suggests more sophisticated approaches.

We begin by discussing quantity (3.1)—a type that combines a number with the unit that is associated with it. By combining numbers and units, we are able to model the world more exactly. With quantities and their units modeled as objects, we can also describe ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required