What's the point of a candidate key?

Question

I\'m fairly new to database management and this question never seems to be answered in more than one sentence. All other SO answers say \"A candidate key is a minimal super

Answer 1

We use candidate key, because some times it is necessary to take care of the record and other issue, for example a data base for bank system, where Account_No is primary key and SocialSecurity_NO will be candidate key, we keep the SocialSecurity_NO as UNIQUE key, because if government got a mistake in providing the SocialSecurity_NO, then it will be big problem, so we have already declared it as UNIQUE key, so there is no possibility that two user with same SocialSecurity_NO will be able for account...

primary key----------- candidate key---------attribute3-------attribute4

Account_No SocialSecurity_NO