field validation can not be repeated

Hello,
I would need to validate a field that is unique in the table and can not be repeated.
the data that they could contain would be alphanumeric.
It would be something similar to the concept "email" or "username" that can not be repeated.
this information is entered using a form.
it's possible?
Alberto
 
P.S. Please try to make some effort to find this stuff for yourself in the wiki rather than asking someone.
 
We are in need of some funding.
More details.

Thank you.

Members online

No members online now.
Back
Top