How to generate unique id in MySQL?

Question

I'm programming a script using PHP and MySQL and I want to get a unique id (consisting of a string: capitals and small letters with numbers) like: gHYtUUi5b. I found many functions in PHP that can generate such numbers but I'm afraid about how to ensure the id is unique!

UPDATE: uuid is long, I mean such id like: (P5Dc) an 11 alphanumeric char.

Answer 1

I use UUID() to create a unique value.

example:

insert into Companies (CompanyID, CompanyName) Values(UUID(), "TestUUID");

Answer 2

You may like the way that we do it. I wanted a reversible unique code that looked "random" -a fairly common problem.

• We take an input number such as 1,942.
• Left pad it into a string: "0000001942"
• Put the last two digits onto the front: "4200000019"
• Convert that into a number: 4,200,000,019

We now have a number that varies wildly between calls and is guaranteed to be less than 10,000,000,000. Not a bad start.

• Convert that number to a Base 34 string: "2oevc0b"
• Replace any zeros with 'y' and any ones with 'z': "2oevcyb"
• Upshift: "2OEVCYB"

The reason for choosing base 34 is so that we don't worry about 0/O and 1/l collisions. Now you have a short random-looking key that you can use to look up a LONG database identifier.