how to build a record index code?

Greetings,
I'm trying to build an index code for each record in the database any help someone can provide will be MUCH appreciated!

The solution could be as simple as incrementing the number in the last record of the database by one.

Ideally, I'd like to build an index code that starts with the the day, the month, a letter, then a 5 digit incrementing number. But I will settle for the simple incrementing number as well. So it looks like this "0701a10004", using today's date, the letter a, and the index number 10004. I think the advanced index solution requires a second number field to increment, then combine it with the date and letter

The code does not need to be displayed in the web form - just needs to show up in the database and be exported.

I am a newbie at programming in Zoho, though I have been able to run a few sample routines.

Thanks!