Re: One to One relationships

>> In general there isn't a good natural key to identify people,
that's why most databases use various surrogates (like SSN.) <<

I call the SSN an external, verifable key and hence "nautral "ay surrogatge key, I mean a key in the system, created by the system and never exposed to the users (it can be binary for all we care). Hash codes, row ids, etc. An artificial key is one we make up internally and do expose to the users (needs check digits, syntax rules, constraints, etc.).

>> I've proposed a natural key for people; the precise latitude,
longitude, altitude and time of their birth. I don't claim that it's a practical system.

Nope! Someone did a study on Astrology and found that in New York City, there are enough maternity ward rooms within 3-4 meters of each other vertically or horizonally that almost 100 children per day are born with the same spatial and temporal co-ordinates. Received on Wed May 07 2003 - 20:30:48 CEST