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Old September 27th, 2005, 06:14 PM
John Vinson
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On 27 Sep 2005 00:38:37 -0700, wrote:

For a Contacts table, last_name, first_name and postal_address makes a
fine natural key


Fred Brown, xxx D Street, Parma, Idaho
Fred Brown, xxx D Street, Parma, Idaho


How on earth do you tell them apart!?


By using other data which you did not include in your candidate key
("Young Fred" and "Old Fred", or "Fred Junior" and "Fred").

John W. Vinson[MVP]