fe_users.email should be unique if "forgot password" is used in fe_login
The email attribute of fe_users is used to identify the tuple, so it should be unique.
ALTER TABLE fe_users ADD unique (email);
(issue imported from #M10728)
#5 Updated by Jigal van Hemert almost 4 years ago
Because it's possible to have several websites in a single installation we can't use the db (within DBAL limitations) to enforce the uniqueness.
In the username property the TCA is already configured to only allow unique username in a folder.
So, instead of changing the db configuration, I'd change the TCA configuration.