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

Silverston c08.tex V2 - 11/21/2008 3:12am Page 446

446 Chapter 8 ■ Business Rules: How Things Should Work

apply this pattern as a very useful way to model business rules because

many business rules, such as product pricing, are so integral to data modeling

efforts. We have found that data modelers will often model rules without even

knowing they are rules. Thus, if you can recognize that this is an ‘if/then’

situation, you can use this pattern to effectively and consistently model this

type of data requirement.

Level 3 Business Rules Pattern

In Figures 8-3 and 8-4 of the previous section you saw two examples of the

Level 2 Business Rules Pattern. In these figures you saw that each of the ‘rule’

entities (EVENT TYPE RULE and PRICE COMPONENT RULE) had their own

distinct entities to maintain the rules, factors, outcomes, and classifications.

However, many of these data model structures had similarities and there are

great advantages to maintaining rules in a single consolidated model. The

essence of the Level 3 Business Rules Pattern is to maintain all types of rules

across an enterprise, or rules for a certain domain area within the enterprise,

using the same data model.

Why Do We Need This Pattern?

You can imagine that by using the Level 2 Business Rules Pattern, there may

be a great number of business rules entities throughout the data model. The

Level 3 Business Rules Pattern addresses the need for ...