Business Rules Approach

Sources:

1. Business Rules Concepts, Third Edition, by Ronald G. Ross
2. Principles of the Business Rule Approach, by Ronald G. Ross

If not stated otherwise, quotes in the presentation below come from this book.

title

Business Rules Approach

author

Bernard Szlachta (NobleProg Ltd)

Business Rule Approach ⌘

Business Operations vs Human Body ⌘

• Structure - bones - fact model
• Power - muscles - business processes
• Control - nervous system - business rules

Relations Rules, Processes and Fact Model ⌘

All three are:

• essential (cannot work on their own)
• interconnected (integrated)
• specialized (one role)
• nervous system is the most important

Structure ⌘

Fact Model (complete skeleton):

• Definition (shape of the bone)
• Term (standard name)
• Wording (ligament)

Power ⌘

• Provided by Processes
• Processes "do what the business needs to get done"

Control ⌘

• Provided by business rules
• Rules constrain procsses

Fact Model ⌘

• Provides the structure
• "Basic things we can know in common about the business"
• "Collective or shared know-how"

Term ⌘

"a word or expression that has a precisely limited meaning in some uses or in peculiar to a science, art, profession, trade, or special subject" Merriam-Webster

Term should be:

• Basic (cannot be derived)
• Countable
• Non-procedural

E.g. Customer, Employee, etc...

Fact Type ⌘

• compared to ligament
• noun-and-verb constructions
• used in business rules
• "recognizes something that can be known"
• in SBVR: meaning of the predicate

e.g:

• customer places order (can be used in a rule: "A customer has always placed at least one order"

Fact Type and UML Class Diagram ⌘

• Fact Model can be translated into UML Class Diagram
• Fact Model is created in order to write rules (from business perspective)
• UML Class diagram is more general concept

"The principal deliverable of fact modeling is a business vocabulary, not a diagram"

Business Rules ⌘

• "A business rule is a rule under business jurisdiction"
• Criterion for making decisions
• Restrict the choice (constraint)
• Must be predictable

Rules, facts, terms and concepts

"Rules build on facts,

and facts build on concepts as expressed by terms.

Terms express business concepts;

facts make assertions about these concepts;

rules constrain and support these facts.”

Rule Types ⌘

• Behavioural Rules (you can break it) (SBVR: Operative Rules)
  • e.g. Every employee must sign employment agreement
• Definitional Rules (cannot be violated directly) (SBVR: Structural)
  • Associate Trainer is a trainer who signed Associate Trainer Agreement
  • Premium Customer is a customer who orders more than $1mln in a calendar year

Definitional Rules can change, definitions do not change

Rules and Events ⌘

• Event is something that happens
• Events should NOT be mentioned in a business rule
• Business rule can be triggered by many events
  • Usually it is at least 2 events
  • e.g. Order must be greater than $100

Rule Independence ⌘

• Separating business rules from processes
• Rules independent from each other
• Rules independent from events

Enforcement Levels ⌘

• Define how we respond to rule violation
• e.g. strictly enforced, deferred enforcement, post-justified override, guideline, etc... (compare BMM)

Rule Categories ⌘

1. Rejector (Constraint)
   • Order total amount must be greater than $100
2. Producer (Production Rules)
   • Early Booking discount is calculated as 5% of total order
3. Projector (Event Rule, Stimulus/response rule)
   • If the invoice is overdue, send a reminder to the customer

See Also ⌘

• http://www.businessrulesgroup.org/brmanifesto.htm

Exercise ⌘

1. For a Pizza Company, create a fact model
2. Write a couple of rules a Pizza Company can have based on the fact model

Pizza Rules Sample Answer