Re: Constraints and Functional Dependencies

On Feb 27, 4:07 pm, mAsterdam <mAster..._at_vrijdag.org> wrote:
> paul c wrote:
> > mAsterdam wrote:
> >> Mp (Marshall/paul) referential integrity =def=
> ...
> >> (using レ = katakana re for references)
>
> >> R(a) レ S(b) ≡
> >> ∀R(a): ∃S(b)| a=b
>
> >> Classic referential integrity (no need, says paul c)
>
> >> (ル = ru for references unique)
>
> (ii)
> >> R(a) ル S(b) ≡
> >> ∀R(a): ∃!S(b)| a=b
>
> > ... Congrats.
>
> Thanks.
>
> Hmm...
>
> Note (afterthought):
> (ii) doesn't need that b should be /defined/ as ck
> for relvar S (which would really be the classic ri),
> just that it /could/ be ck in the current relvalue S.
>
> About the notation:
> Note (not afterthought):
> 1. that the katakana re, レ for _reference_ could read as 'check'
> (it looks like a check mark),
> verbose 'check that there is',
> and
> 2. the katakana ru, ル for _reference_unique_ as 'check one'
> (it looks like a check mark with a sloppy 1 before it),
> verbose 'check that there is only one'.
>
> How about that for sugar coating ;-)

The idea of using katakana, esp. with abbreviations in English, to expand the symbol set, is madcap brilliance. Omedeto gozaimasu!

Marshall Received on Wed Feb 28 2007 - 06:52:38 CET