Logic's Role in Analysis

1. Deductive: What applies to all cases applies to all observed cases. This is possibility. Philosophy.
2. Inductive: What applies to all observed cases applies to all cases. This is probability. Science.
3. Didactic: What applies to one case applies to all observed cases. This is morality. Fable.
4. Anecdotal: What applies to one observed case applies to all cases. This is biography. History.

All of these forms of logic come into play when you are designing a database. Preference has to be given to inductive logic because it is using repeated, measured experience to guide design.

Deductive reasoning often happens when the governing user dictates the business rules without consulting with the frontline users.

Didactic reasoning is encountered when scenarios are invented to deal with edge cases that have never happened.

Anecdotal reasoning is encountered when scenarios that only occurred once are factored into the design.

Deductive, Didactic and Anecdotal reasoning bogs down an otherwise clean analysis and design. Recognize them for what they are and work them out during analysis if possible and definitely during design.