I have a website that uses the social stuff from spring social showcase example. I recently removed the username because I just want the the user to login using the email. This is working fine but I populate the email into the userConnection.userId column. If however the Facebook email is changed would this cause any problems?

In the original example if the user changes his id (i think it is possible), would it be updated or would it just be outdated in the table or create a new row? Either way it might cause problem.