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  1. #1
    Join Date
    Jun 2011

    Unanswered: Primary Key or Super Key or Candidate Key

    Hi everybody,

    Hi I am preparing for my database exams. I hope this is the best place to clear my doubts.

    Attributes-Customer Name, Social Security number, Age, Address

    Could you please clear my doubt?
    Is Social Security number a primary key or super key or candidate key?

    I have confusion with these three terms. Please clear my doubt

    Thank you

  2. #2
    Join Date
    Dec 2007
    London, UK
    A primary key is a candidate key and any candidate key is a superkey. The only interesting questions raised by your example are whether it makes sense to enforce uniqueness of a Social Security Number or even to expect customers to supply their SSN at all. Probably not. Without a clear statement of the business requirements you are trying to model it's not really possible to give a more useful answer.

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