SQL Keys in Depth
"For instance, a database of hobbyist club members could include uniqueness on the two columns first_name, last_name of members. Duplicates are likely unintentional at this scale, and if necessary the constraint can be dropped. Until an actual conflict happens the key is a reasonable precaution."<p>Absolutely do not do this.<p>People have names that are duplicates. A situation where someone is unable to join a club because their name clashes with an existing member is not OK.<p>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!