Re: what are keys and surrogates?

From: rpost <rpost_at_pcwin518.campus.tue.nl>
Date: Thu, 14 Feb 2008 18:54:57 +0100
Message-ID: <f387a$47b48071$839b4533$30541_at_news1.tudelft.nl>


JOG wrote:

>Ok, so if I read you right, you have been supplied with some facts
>such as:
>
>1) A and B begat C
>2) C and D begat A
>3) A and E begat F
>etc.

No, that is not right. The facts (more accurately: updates) look like this:

A, the son of B, the son of C, the son of A, the son of A, the son of B, and X, the daughter of Q, the son of B, the son of B, ....   begat Q

etc.

>Your argument is that, because A is the name of two people (obviously
>A and C can't be the parents of each other) we should use OID's to
>distinguish them. Have I read you correctly there?

I'm afraid not. Did you look at the Jesus example?

>Just imagine the query:
>User: "Did A beget F?"
>DB: "I don't know. Its ambiguous. What's the OID of the A you are
>talking about"
>User: "You know what, strangely I don't seem to be able to find that
>in the bible..."

It is exactly the *point* of the example that names alone do *not* identify persons, while every person is still fully identifiable in the database, owing to the oids. (And constraints such as the ones I mentioned.)

-- 
Reinier
Received on Thu Feb 14 2008 - 18:54:57 CET

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