Can I take my other question, please? Please correct me if I read your poorly thought:
Standardization of the email is not the main priority. But do we agree on principle that email address can contain a code to operate on the database?
It would be the priority? I confess not to be very strong in SQL that is not my part of the more advanced skills in computer. What worries me is found to have emails with extensions longer than 20 characters .... Concerning security can be better, right?