Only allow 1 submission from an email address in webform

Question

I am taking some users information using webform, which is their name and email address.

I need to only allow one submission per email address, restricting the form by IP or cookie in the webform settings is not sufficient in this case.

Is this possible?

Answer 1

Edit the email field in the webform and check both the "mandatory" and "unique" options.

In this case, it would accept entries only for unique mail id's