Guideline 1: Each fact should have a real-world business equivalent.
Guideline 2: Focus on determining business-related facts that represent
either:- Business transactions or business events
or:-Business objects whose state is of interest for the information analyst
or- Business objects whose state changes are of interest for the informationanalyst Whether or not a state model or a state change model (or both) will be used to represent facts in the dimensional model depends on the interests of the information analyst.
Guideline 3: Each fact should be uniquely identifiable, merely by the existence of its real-life equivalent.
Guideline 4: The granularity of the base dimensions of each fact should be as
fine-grained as possible.

These guidelines can be used either to drive the dimensional modeling process
or to assess and enhance an initial dimensional model, developed on the basis
of business query analysis.