Fact-orientation
People communicate facts, that is the fact is the unit of communication. The fact-oriented approach enables multidimensional categorization.
- The fact-oriented approach supports time changeability.
- The fact-oriented approach provides semantic stability.
- The fact-oriented approach enables extensibility and reuse.
- The fact-oriented approach involves breaking down compound fact types into elementary (atomic) ones.
Conceptual formalization describes a business domain, and is composed of 1) a conceptual schema (fact structure) and 2) a population of ground facts. A business domain (universe of discourse) comprises those aspects of the business that are of interest.
The schema declares:
- the relevant fact types (kinds of ground fact, e.g. Employee works for Department)
- the relevant business rules (typically constraints or derivation rules).
A fact is a proposition taken to be true by the business. Population facts are restricted to elementary and existential facts.
Constraints can be static or dynamic:
- A static constraint imposes a restriction on what fact populations are possible or permitted, for each fact population taken individually e.g. Each Employee was born on at most one Date.
- A dynamic constraint imposes a restriction on transitions between fact populations
e.g. a person’s marital status may change from single to married, but not from divorced to single
Derivation of facts.
- Derivation means either, how a fact type may be derived from one or more other fact types e.g.
- Person1 is an uncle of Person2 if Person1 is a brother of some Person3 who is a parent of Person2
- Or, how a noun concept (object type) may be defined in terms of other object types and fact types e.g.
- Each FemaleAustralian is a Person who was born in Country ‘Australia’ and has Gender ‘Female’
Read more about this topic: Semantics Of Business Vocabulary And Business Rules