Re: Artificial Primary keys
Date: Mon, 28 Jan 2002 21:25:08 +0000
In message <c0d87ec0.0201281124.3d42e78f_at_posting.google.com>, --CELKO--
>>> Or could you give an example - that is: of a natural key that holds
>information, but is immutable? <<
>But we settled for fingerprints when I worked for the prison system
There is a very small but nonzero probability that two individuals could have the same DNA sequence because there is no authority or physical law that enforces uniqueness.
There's some debate about fingerprints, it even has some relevance to this newsgroup.
I'm told that there is a difference in the way that fingerprint comparisons are made in the US and the UK. I'm told that in the US there is a coding system used to represent fingerprints, a sort of hash function, and that the courts accept that there is a match when two sets of prints hash to the same value.
-- Bernard Peek bap_at_shrdlu.com In search of cognoscentiReceived on Mon Jan 28 2002 - 22:25:08 CET