Re: Database design, Keys and some other things

Gene Wirchenko wrote:
> >P = { <feature: sky>, <colour: blue>, <period: daytime> }
>
> >The extra information I specified in the previous post however, is
> >absolutely not part of this statement about the world. Rather it is
>
> Of course it is. If nothing else, it is bibliographic, but I
> would restructure the statement to:
> [Gene's P =] James says that [James's] P.

If you are saying there is a distinction between the observer of the
proposition and the creator of the tuple, just as there is a
distinction between the time of the observation and the time of the
tuples creation in the db, well, yes I agree. This was the intention of
the example, although it may have become obfuscated along the way. But
there is a distinction, and if Gene were the person who observed the
the fact that the sky is blue in the day, we have:

P = { <feature: sky>, <colour: blue>, <period: day>, <observer: Gene>}

M = { <creator: James>, <created: 1127871055>, <statement: P> }


P is just a finite partial mapping, and as such my (granted often
unreliable) spider-sense is still telling me that like any function,
there may exist relationships that do not belong as part of P's
extensional representation (orderings, set membership, etc). Easy
employment and manipulation of these would utilise an implicit
conceptual reference (as I would use the letter P in the mathematical
notation - but instead I have to hack in and manage an explicit
artificial key, or specify "on update cascade"s all over the shop to
maintain integrity.)


On a side note, it has of course been pissing it down in the UK, and
the sky is absolutely, categorically and unequivicably, not blue :)

.

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