A Guide To The Candidate Key
Properties of a Candidate Key All candidate keys have some common properties. One of the properties is that for the lifetime of the candidate key, the attribute used for identification must remain the same. Another is that the value cannot be null. Lastly, the candidate key must be unique. For example, to specifically and uniquely identify each employee, a company might use the employee’s Social Security number. Some people share the same first names, last names, and position, but no two people use the same Social Security number....