Question

I have a database table where every row has its unique ID (RowID).

Is there a good way to convert this RowID to a unique key that is always 6 characters in length. Unique key characters can be {A-Za-z0-9}. One example of unique key would be: a5Fg3A.

Of course I do realize there’s only certain number of keys I can generate using this method but that doesn’t matter for my case.

I’ve thought much about this but I can’t come up with an algorithm that would be able to do this properly.

One idea I had was:
Unique key = RowID
If RowID is lower than 100000 then append 0 in front of it, for example:
123 becomes 000123
1 becomes 000001

Then for numbers in the range of 100000 to 900000 I would replace first number to a string, e.g. 0 = a, 1 = b, 2 = c, …, 9 = j.

Then I could do the same with capital letter, etc.

My problem is that my algorithm is very limited and generates low number of keys because it wouldn’t utilize all possible characters.

So basically I should be able to generate 56800235584 unique keys assuming every key is of length 6 and utilizes these characters: {A-Za-z0-9}.

A-Z = 26 characters
a-z = 26 characters
0-9 = 10 characters

So it’s 62^6 unique keys.

Any feedback would be appreciated on how this could be done properly (or even optimal) 🙂

Thanks!

Answer 1

If you want to make A-Z a-z 0-9 to be the alphabet as you noticed you have base 62 number system. So encode the unique rowid in base 62, there is a standard algorithm to do so. If your application allows (needs) it you can add a few more printable characters like ‘+’, ‘/’, ‘!’, ‘@’.. so you get more uniques. The ready made answer is base64 encoding, widely used.