SBVR 1.5 RTF Avatar
  1. OMG Issue

SBVR15 — Revise Modeling of Fact Model and Conceptual Schema

  • Key: SBVR15-17
  • Legacy Issue Number: 13150
  • Status: open  
  • Source: Hendryx & Associates ( Stan Hendryx)
  • Summary:

    understand you will be discussing the topic of packaging SBVR tomorrow, and I want to provide a perspective on this topic and make a request.

    In my view, the key packaging concepts “fact model” and “conceptual schema” need to be in the normative SBVR metamodel to support widespread sharing and reuse of SBVR models. We want to promote the development of libraries of SBVR fact models and conceptual schemas and to compose fact models and conceptual schemas from other fact models and conceptual schemas. The ability to package these in a standard way is crucial to this end. A normative approach to globally identifying these models is needed to support their sharing and reuse. Concepts of packaging, identification, and composition of fact models and conceptual schemas are preferably included in Clause 8. As the most basic compliance point, Clause 8 needs to be expressible in terms of itself, and to include concepts for packaging, identification, and composition of fact models and conceptual schemas. I understand a proposal is under consideration to move “fact model” and “conceptual schema” entries to Clause 10. This would be a mistake, as we would then have no normative way of specifying the packaging.

    The definition of “conceptual schema” should be refined to reflect the fact that a conceptual schema is a kind of fact model. The distinction between a conceptual schema and other fact models is that a conceptual schema includes at least one fact that asserts the existence of a concept. Other fact models that are not conceptual schemas contain only ground facts. The text of SBVR makes it clear that a conceptual schema is a fact model, that every SBVR interchange document is a fact model. That “conceptual schema” specializes “fact model” should be reflected in the definition of “conceptual schema.”

    The term “vocabulary” is not used in the SBVR specification consistently with its definition as a “set of designations and fact type forms…” Each of the normative clauses of SBVR, called a “Vocabulary,” is actually an annotated conceptual schema. A conceptual schema comprises a “combination of concepts and facts (with semantic formulations that define them)…” The designations and fact type forms in each SBVR normative “Vocabulary” constitute the vocabulary of that “Vocabulary”. The definitions and necessities in the SBVR entries are statements of schema facts. The notes and examples are annotations of the conceptual schema. Ability to include annotations is crucial to practical development and use of any model, and is universally provided for in other and modeling and programming languages. It should be possible to normatively include annotations in a SBVR conceptual schema or fact model. Accordingly, it is recommended that “description” and related concepts of notes and examples in Clause 11.2.2 be moved to Clause 8 to support annotation of fact models. With respect to the semantic formulations of a conceptual schema, it is preferred that Clause 8 only include statements of the definitions and schema facts, and leave it to Clause 9 to include the semantic formulations of these. Either “vocabulary namespace” and fact types that use the term should be moved to Clause 11, or “vocabulary” should be moved to Clause 8. The concept “vocabulary” is not necessary in Clause 8 but might be conveniently located there. Namespaces adequately serve the purpose of organizing designations and fact type forms. It is suggested the RTF consider providing recommendations for naming conventions for URIs of namespaces and related conceptual schemas that define and constrain the concepts represented by the designations and fact type forms in the namespaces.

    Here are some suggested entries for Clause 8 that show how the concepts described above might be modeled:

    conceptual schema

    Definition: fact model that includes at least one existential fact asserting a concept

    Note: This definition extends the definition of ‘conceptual schema’ in SBVR to formalize that a conceptual schema is a kind of fact model. This is evident in the specification text, but is not included in the current definition.

    Note: The facts of a conceptual schema in addition to the concept existential facts describe what is possible, necessary, permissible, and obligatory in each possible world of the domain being modeled.

    Note: Two levels of formalization of fact models (including conceptual schemas) are possible. 1) A fact model may contain only statements of definitions and other facts and not their semantic formulations. In this case, the fact model can meet the Meaning and Representation compliance point, 2.2.1. 2) A fact model may contain semantic formulations of its definitions and facts, in which case the fact model can meet the Logical Formulation of Semantics compliance point, 2.2.2.

    fact model1 includes fact model2

    Note: This fact type enables recursive composition of fact models and conceptual schemas.

    Necessity: This fact type is reflexive, antisymmetric, and transitive, i.e. related fact models are at least partially ordered.

    fact model includes description

    Note: This fact type enables the annotation of fact models and conceptual schemas.

    thing has URI

    Note: This fact type enables modeled things to be identified globally for future reference.

    I am requesting that these concepts, or some refinement of them, be included in the next release of SBVR.

  • Reported: SBVR 1.0 — Wed, 10 Dec 2008 05:00 GMT
  • Updated: Tue, 3 Jan 2017 13:19 GMT