> Expecting a club administrator to be able to drop a uniqueness key from their database in order to resolve this situation is not a reasonable solution!
Especially since if you have any FK relationships, and that was the only candidate key for the members relation (and why have such a bad key if it's not the only one), you then need to add new attributes to create a new key, populate it to all existing roles, change all existing FK relationships and associated queries, on top of the easy part, which is dropping the old unique constraint.
Especially since if you have any FK relationships, and that was the only candidate key for the members relation (and why have such a bad key if it's not the only one), you then need to add new attributes to create a new key, populate it to all existing roles, change all existing FK relationships and associated queries, on top of the easy part, which is dropping the old unique constraint.