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

Silverston c03.tex V2 - 11/21/2008 2:59am Page 98

98 Chapter 3 ■ Using Roles: How Parties Are Involved

What Are the Weaknesses of the Pattern?

The weaknesses of this pattern are as follows:

By adding the PARTY ROLE concept you are adding a level of general-

ization that may be difficult to gain buy-in for from some enterprises.

Some enterprises don’t view PARTY ROLE as different from PARTY.

The view that ‘‘you are what you do’’ is prevalent in many different

enterprises. This view is not wrong. It is a valid alternative and is dis-

cussed in ‘‘Level 2 Contextual Role Pattern, PARTY Only Alternative.’’

This pattern forces XYZ Corporation to use declarative roles.Inother

words, if XYZ Corporation discovered a new contextual role, such as

‘‘Project risk officer,’’ they would have to attach to a declarative role.

What happens if there are no declarative roles defined that support this

role? XYZ Corporation would have to create this new declarative role as

well as the new contextual role.

NOTE

It could be argued that the weakness just mentioned is in fact a

strength. In enterprises that have strict data policies it may be desirable to

force the use of declarative roles for all contextual roles. Additionally, this

pattern could be expanded to allow the use of contextual-only roles and just

relate the entity at hand to a role entity that is not declared as a declarative

role. For example, there could be a role ...