The Data Model Resource Book, Volume 3: Universal Patterns for Data Modeling

Silverston c03.tex V2 - 11/21/2008 2:59am Page 73

What Is a Contextual Role? 73

to model what people and organizations do in terms of specific business

activities or entities. The chapter describes how each pattern supports the

attributes and relationships involved in modeling contextual roles.

Like most of the chapters in this book the style of modeling for each of the

patterns starts with the most specific style (Level 1 Contextual Role Pattern) and

progresses through the chapter to a more generalized style (Level 3 Contextual

Role Pattern). The different levels of generalization may be applicable to

different enterprises or styles of modeling. At the end of the chapter we also

describe a ‘‘hybrid’’ pattern that combines both the specific and generalized

style of modeling in a single pattern. In summary, this chapter includes:

The definition of a contextual role

The different levels of contextual role patterns

When to use and not to use different contextual role patterns

Insights into each pattern

The relevance of each pattern

A synopsis of each of the patterns, pros and cons, and when to use and

not use them

What Is a Contextual Role?

Context can be defined as ‘‘the circumstances in which an event occurs; a

setting,’’

2

and a role can be defined as ‘‘the actions and activities assigned to

or required or expected of a person or group.’’

3

So, what does this mean in

terms of our pattern? What is being described ...