ID Capacity — The Math Behind Choosing the Right ID Length

The main aim of this article is to describe the limitations of ID, in terms of capacity, and the math behind the scene. Alright, good people — ID is not complicated. Various methods can generate it, such as using a counting number, randomizing, or composing/concatenating from multi-attributes (like a national ID or college student ID). Sometimes one can ignore it because the ID is auto-generated in the database, like MongoDB. But what if we must find out how to make the ID as short as possible?