SBVR Speaks: (1) The Key Notions of the SBVR Approach

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In January 2008, the "Semantics of Business Vocabulary and Business Rules" (SBVR) was first presented by the Object Management Group (OMG) as an official specification of the OMG.  Version 4 (SBVR 1.4) was published in 2017.[1]

An understanding of the "Semantics of Business Vocabulary and Business Rules" (SBVR) begins by understanding the three elements of its title:

  • Semantics,
  • Business Vocabulary, and
  • Business Rules

This introductory article explains what these three key notions mean in the SBVR approach.

What is Semantics?

Semantics is "the meaning or relationship of meanings of a sign or set of signs."[3]  In SBVR, these signs are not limited to text; they can be of any form:  words, phrases, codes, numbers, icons, sounds, etc.

SBVR standardizes two important areas of semantics:

  1. Business vocabulary semantics, which deals with all kinds of terms and meanings (other than meanings of business rules)

  2. Business rule semantics, which deals with the specification of the meaning of business rules in terms of the business vocabulary

What is a Business Vocabulary?

A 'business vocabulary' contains the specialized terms, verbs, and concepts definitions that a given organization or community uses for talking and writing in the course of everyday operation.

The core vocabulary concepts of SBVR are based on ISO terminology standards:

  • ISO 1087-1 (2000) "Terminology work — Vocabulary — Theory and application"
  • ISO 704 (2000) "Terminology work — Principles and methods"
  • ISO 860 (1996) "Terminology work — Harmonization of concepts and terms"

These standards have been used over many decades for multilingual vocabularies in support of language translation work.  SBVR is the result of the integration of these ISO standards, formal logics, linguistics, and practical experience from SBVR team members[4] who are foremost practitioners in the fields of business vocabulary and business rules.

There are additional ISO standards for representing basic concepts such as country names and codes (ISO/IEC 3166), dates and times (ISO/IEC 8601), currency codes (ISO/IEC 4217), addresses (ISO/IEC 11180).  While these are likely to be adopted into vocabularies that apply SBVR as a matter of practice, they have not been included directly in the SBVR standard.

What is a Business Rule?

The SBVR applies a common-sense definition of 'business rule':

business rule:  rule that is under business jurisdiction

'Under business jurisdiction' is taken to mean that the business can enact, revise, and discontinue business rules as it sees fit.  If a rule is not under business jurisdiction in this sense, then it is not a business rule.  For example, the 'law' of gravity is not a business rule.  Neither are the 'rules' of mathematics.

The more fundamental question in defining 'business rule' is the meaning of 'rule' itself.  The SBVR team carefully considered a variety of real-world interpretations of 'rule', including numerous authoritative dictionaries and previously-published works on business rules.  Foremost consideration was given to how people think naturally about 'rule' in everyday life, not only within business activities but also outside of them.  For example, several rulebooks for professional sports were reviewed.

Intuitively, 'rule' carries the sense of 'guide for conduct or action' both in everyday life and in business.  In one way or another, this sense of 'rule' can be found in most, if not all, authoritative dictionaries.

On closer examination, it should become obvious that if rules are to serve as guides for conduct or action, they must also provide the actual criteria for judging and guiding that conduct or action.  In other words, for the context of business rules (and probably in most other contexts), rules serve as criteria for making decisions.  SBVR's interpretation of 'rule' therefore encompasses the sense of 'criterion' as given by authoritative dictionaries.

This point is fundamentally important for professionals creating business models.  In business process engineering, for example, the most prevalent understanding of 'business rules' is as criteria for decision points ('branch points') in business process models.  Often such decision points are relatively simple — for example, "Do we treat a customer as gold level, silver level, or bronze level?"  In other cases, such decision points may be highly complex — for example, "Should an insurance claim be paid, denied, or considered as possibly fraudulent?"  For these more complex cases (in particular), special inferencing techniques are quite likely to be helpful — for example, tools supporting 'production rules'.

Rules and Formal Logic

An additional (and no less important) driver in the SBVR's treatment of rule is consistency with formal logics.  Notable experts in this area recommended that the best treatment for the SBVR interpretation of rules would involve obligation and necessity claims.  Consequently, in SBVR a 'rule' is "proposition that is a claim of obligation or of necessity."

The two fundamental categories of rule are:

  1. Behavioral Rules (obligations), also known as 'operative rules'. 
    These are rules that govern the conduct of business activity.  In contrast to definitional rules, behavioral rules are ones that can be directly violated by people involved in the affairs of the business.  For example (from EU-Rent):
Obligation:  A customer who appears intoxicated or drugged must not be given possession of a rental car.
  1. Definitional Rules (necessities), also known as 'structural rules'. 
    These are rules about how the business chooses to organize (i.e., ''define' or 'structure') the things it deals with.  Definitional rules supplement concept definitions.  For example (from EU-Rent):
Necessity:  A customer has at least one of the following:
    •  a rental reservation,
    •  an in-progress rental,
    •  a rental completed in the past 5 years.

Rules, Verb Concepts, and Noun Concepts expressed by Terms

Informally, a verb concept can be understood as an association[5] between two or more noun concepts — for example, the "is located at" connection between 'rental car' and 'branch' in "rental car is located at branch."  In SBVR, rules are always constructed by applying necessity or obligation to some verb concept(s).  For example, the rule 'A rental must not have more than three additional drivers' is based on the verb concept 'rental has additional driver'.

By this means, SBVR realizes a core principle of the Business Rules Approach at the business level, which is that "Business rules build on verb concepts, and verb concepts build on noun concepts as expressed by terms."  This notion is well documented in published material by foremost industry experts since the mid-1990s.[6]

One important consequence of this aspect of the SBVR approach is that concepts (including verb concepts) are distinct from rules.  In fact, in SBVR there are separate Compliance Points.  This design permits SBVR's support for concepts (including verb concepts) to be used on its own to assemble business vocabularies that are independent of the rules governing the business.

Practicable vs. Automatable

All business rules need to be practicable.  This means that a person who knows about a business rule could observe a relevant situation — including his or her own behavior — and decide directly whether or not the business was complying with the rule.  This assumes, of course, that the business vocabulary on which the rule is based has been adequately developed and has been made available in some appropriate manner.  This points toward the essential role of business vocabulary in supporting business rules; indeed, the bulk of SBVR is devoted to the area of vocabulary.

Just because business rules are practicable does not imply they are always automatable.  Many business rules — especially behavioral business rules — are not automatable in IT systems.  For instance, consider the example EU-Rent obligation given above.

This distinction is not important within SBVR, however, since its focus is on rules only from the business perspective, regardless of whether the rules might be automated.  This will become important in defining a transformation from business model to PIM.[7]  In particular, non-automatable business rules need to be implemented as user activity, supported by procedure manuals or rulebooks.

References

[1]  Semantics of Business Vocabulary and Business Rules (SBVR).  Object Management Group.  The current version of SBVR is available on the OMG site.  return to article

[2]  Quick Reference for Basic SBVR Terminology (v. 1)

[3]  Merriam-Webster Collegiate Dictionary.  return to article

[4]  The original BRT (or, Business Rules Team) was a multi-national consortium, formed expressly to respond to the OMG's "Business Semantics of Business Rules" RFP.  BRT members, along with other individuals, then worked as the SBVR Finalization Task Force, the group that brought SBVR 1.0 to completion in December 2007.  Work has continued by a succession of SBVR Revision Task Force teams, each working to complete an enhanced version of the specification.  return to article

[4]  'Association' is used here in its everyday, business sense — not in the narrower, technical sense that would apply (for example) to a UML class model.  return to article

[5]  SBVR also supports the special case of 'unary verb concept', which is termed 'characteristic'.  return to article

[6]  The Business Rules Group, Business Rules Manifesto:  The Principles of Rule Independence, ver. 1.2 (Jan. 8, 2003).  Available at the Business Rules Group's site (in English as well as translations to numerous other languages).  The core principle mentioned above — sometimes called the Business Rules Mantra — was often originally stated:  "Rules build on facts, and facts build on terms."  The SBVR version of this principle is its own, more precise (formal) counterpart.  return to article

[7]  'Platform Independent Model' in the OMG's Model-Driven Architecture (MDA).  return to article

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Standard citation for this article:


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S. BVR , "SBVR Speaks: (1) The Key Notions of the SBVR Approach" Business Rules Journal Vol. 6, No. 12, (Dec. 2005)
URL: http://www.brcommunity.com/a2005/b263.html

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S.   BVR
S. BVR The SBVR Team, Semantics of Business Vocabulary and Business Rules

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