User management hints

[Germano Paciocco]

Hi everyone.
I'm new to Freeradius, and I would like to write a very simple user
management php/mysql script, that should allow me to do some simple
things:

1) create a user;
2) set expire date for a user;
3) disable user, automatically at expire date or manually if needed.

I installed successfully freeradius with mysql on a debian box and
tested a new user with radtest.
I also began to study sql schema, but I can't find many information on
internet about it.
Can anyone you suggest me some good documentation, just to begin?
Thank you very much.
Regards.

--
GP