makeid function - lafnlab/Amore GitHub Wiki

In most software that uses relational databases, the primary key is an auto-incremented number. This means the first entry a table will have primary key of 1, the second entry will have a primary key of 2, and so on. While this isn't bad for most purposes, the numbers can become staggering if a website becomes popular.

For example: Jack Dorsey sent his first tweet in 2006. Three years later, Twitter had reached a billion tweets. Now (late 2018), Twitter gets around a billion tweets every two days.

However, there's no reason that a primary key has to be a number. The purpose of a primary key is to provide a unique reference to a record. Because of that, and because I'm probably subconsciously making things unnecessarily difficult for myself, the function makeid was born.

The function starts with a string of 189 characters which includes digits, and uppercase and lowercase Latin and Cyrillic letters. The string is split into an array with preg_split. The array is randomized with PHP's shuffle function. The randomized array is turned back into a string with join. The actual id is made when mb_substr takes the first 10 characters from the string and passes it back to wherever the makeid function was called.

In theory, this could produce some duplicates, so I always check the database to make sure the id isn't being used before inserting it into the table. For now it works. Here's some stats:

Power	Possibilities	Shorthand
189^1	189	less than 200
189^2	35,721	36 thousand
189^3	6,751,269	6.8 million
189^4	1,275,989,841	1.3 billion
189^5	241,162,079,949	241 billion
189^6	45,579,633,110,361	45.5 trillion
189^7	8,614,550,657,858,229	8.6 quadrillion
189^8	1,628,150,074,335,205,400	1.6 quintillion
189^9	307,720,364,049,353,800,000	308 quintillion
189^10	58,159,148,805,327,867,842,601	58.2 sextillion