Great article, but there's a terrible mistake on the part of the engineer that you gloss over here.

There are two very different entities in two very different worlds. One is the string "Null" which is a list of characters, but the other is the coding entity named NULL which is a completely different sort of fish that lives in the programming language world.

Under no circumstance should that name Null even enter the programming language world. This is a truly terrible mistake, one that's responsible for so, so, so many hacks, exploits and other catastrophes.

XKCD as always explains it well. https://xkcd.com/327/

Thanks for a good read!