Constraints and Functional Dependencies - comp.databases.theory

Bericht van Constraints and Functional Dependencies-discussie

mAsterdam

Meer opties 27 feb 2007, 22:44

Nieuwsgroepen: comp.databases.theory

Van: mAsterdam <mAster...@vrijdag.org>

Datum: Tue, 27 Feb 2007 22:44:33 +0100

Lokaal: di 27 feb 2007 22:44

Onderwerp: Re: Constraints and Functional Dependencies

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Marshall wrote:
> mAsterdam wrote:
>> Does this (unicode 2261)
>> come through: ≡ or does it look like gibberish?

> Yes, that's the one. Comes through just fine. (It's always
> a shock when my browser renders anything more challenging
> than ASCII.)

Brace yourself before you scroll down :-)

Playing a little with Unicode:

Mp (Marshall/paul) referential integrity =def=
forall R(a): exists S(b): a = b

becomes

R(a) references S(b) ≡
∀R(a): ∃S(b)| a=b

(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)

R(a) ル S(b) ≡
∀R(a): ∃!S(b)| a=b

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