Note: "Then & Now" (t&n) is a new version of what used to be the "Oldies but Goodies" (OBG) series. To demonstrate the superiority of a sound theoretical foundation relative to the industry's fad-driven "cookbook" practices, as well as the disregarded evolution/progress of RDM, I am re-visiting my old debunkings, bringing them up to the current state of knowledge. This will enable you to judge how well arguments have held up and realize the increasing gap between industry stagnation -- and scientific progress.
(This a revised version of an earlier post with clarity improvements).
Q: “What would you suggest for a datetime field where the value is not known and should therefore be not-applicable?”While searching through records I came across an old consulting project involving the migration of a neo-natal research database from Focus -- an old hierarchic DBMS -- used to record extensive details about hundreds of monthly births at a university hospital for more than 20 years. The person who had designed the Focus database was the only one who knew and understood its complexity sufficiently to maintain it. Each time a researcher needed some subset of data to analyze, he would extract it and serve it upon request. Aside from the inefficiency of the process, the person was retiring at a time when hierarchic DBMSs reached the end of their usefulness, Focus experts were already few and expensive and "relational" (read: SQL) was the dominant fad.
A: ”NULL sounds good to me.”
