Re: Because computer dates are numbers but real dates aren't
I was involved in writing a few systems for the local NHS in the 1980s and 1990s, using Clipper. I bottled out and stored all dates as strings in the YYYYMMDD from the beginning and so had a slight overhead in some aspects of processing but indexing, grouping, etc. was easy.
I was asked to confirm in writing (and, for all I knew, sign my life and first-born away) that the system was Y2K compliant. I took the easy option, said that my software was, their hardware...maybe...other software involved...certainly not, and so I couldn't sign off.
As they say, I never worked in that town again. :-)
Ironically, through the early 2000s I got contacted by other NHS units that was using the software I'd written that I didn't know had it, and they had no problems. I must have got something right.