On Sun, Nov 8, 2015 at 2:42 PM, John McKown <john.archie.mckown at gmail.com> wrote: > (...) What if the person is alive? What if you don't now the birth day?).
NULLs, as you mentioned, are questioned in many domains. They provide an easy solution, but never the only one there is. In an OOP system, for instance, LivingPerson and DeadPerson may be two different classes and have different properties. In a RDBS, a table could store the people that have not died yet. Or you could use strings of the form "<DoB>-<DoD>" and have some "1995-02-11-" strings for the ones still living. But there is a "semantic" nullity there if you think about it. -- Bernardo Sulzbach
