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What Is An Artificial (derived) Primary Key? When Should It Be Used? |
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Answer» Using a name as the primary KEY violates the principle of stability. The social security number might be a VALID choice, but a foreign EMPLOYEE might not have a social security number. This is a case where a DERIVED, rather than a NATURAL, primary key is appropriate. A derived key is an artificial key that you create. A natural key is one that is already part of the database. Using a name as the primary key violates the principle of stability. The social security number might be a valid choice, but a foreign employee might not have a social security number. This is a case where a derived, rather than a natural, primary key is appropriate. A derived key is an artificial key that you create. A natural key is one that is already part of the database. |
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