Re: identity columns

In message <c0d87ec0.0201091026.68b33772_at_posting.google.com>, --CELKO-- <71062.1056_at_compuserve.com> writes
>>> If you insist on a true natural key then get your employees to
>specify the place and time of their birth. Getting the time to a
>precision of 1 second and the latitude, longitude and altitude to a
>precision of ~1ft should guarantee
>uniqueness. <<
>
>That one does not work unless you have insanely good precision in both
>time and space.

It does work if your precision in time and space is adequate. I wasn't proposing it as a practical way of identifying people. I still maintain that there is no easy to use natural key for identifying people so if you have a table that has to record people then you have to use an artificial or surrogate key.

> They did a study of Astrology looking at hospital in
>New York City. The number of people born each day with EXACTLY the
>same horoscope was quite high. An orthodox Jewish hospital is in the
>same area as a public hospital that services a poor Latino
>neightborhood, etc.

 From what I know of astrology it's possible to use the precise place and time of birth to prepare an individual chart. I've seen charts that use time to the nearest minute and position to the nearest minute of arc. I'm not sure how the variables are quantised.

-- 
Bernard Peek
bap_at_shrdlu.com

In search of cognoscenti