So have another column adjacent to the date that stores an enum with an error code with a reason for why the date is missing. My point is, this is business logi

So have another column adjacent to the date that stores an enum with an error code with a reason for why the date is missing. My point is, this is business logic, doesn't have a universally applicable definition, and should be handled on a case-by-case basis rather than trying to hard-code it into the date type in the DB. Default date types, with some columns being nullable, work just fine for my project. I wouldn't want them to be more complicated and force me to consider additional cases, especially if those cases aren't language compatible.