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Re: Constraints and Functional Dependencies: Notation

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Fri, 02 Mar 2007 03:06:41 +0100
Message-ID: <45e78636$0$326$e4fe514c@news.xs4all.nl>


Cimode wrote:

[snipped Unicode test]

> mAsterdam wrote:

>> Mp (Marshall/paul) referential integrity 
>> (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

>
> Thank you for the formatting effort...For better formalism, domain of
> values -a- and -b- must be specified
>
> So I may suggest ...
>
> --Reference
> R(a) レ S(b) ≡∀a E R,∀R(a): ∃b E S | ∃S(b) | a=b

Would you care to verbosely expand "∀a E R,∀R(a)"?

Just to show I'm not trying to let you do all the work, I'll take a compound guess.
I may be completely off, but please remember: I am asking you.

Guess 1: You'd want to include some way of denoting types/domains ("For better formalism").

Guess 2: You'd want to notationally differentiate between attributes and attribute values.

Guess 3: You actually were looking to write:

        ∀a ∈ R,∀R(a)

, using the Set-notation ∈, element of' (Unicode 2208) sign, for something similar, but slightly different.

Guess 4: You did not yet read my first response to Marshall's OP, expressing both

	a worry + suggestion about the OP's ambiguity
	between (set of) attribute(s) and (set of)
	attribute values  and
	
  	a - strictly notational - shorthand:

>> So, let's have a notational shorthand: A' is an instance of A.
>> 

>> A = {a1, ... an}
>> A' = {a1', ... an'}

If I am right please do so now,
http://groups.google.nl/group/comp.databases.theory/tree/browse_frm/thread/49a8420d5421274e/cb23e0894d1814c0?rnum=81&hl=nl&q=Constraints+and+Functional+Dependencies&_done=%2Fgroup%2Fcomp.databases.theory%2Fbrowse_frm%2Fthread%2F49a8420d5421274e%2F8d9829b9203e3cf2%3Flnk%3Dst%26q%3DConstraints%2Band%2BFunctional%2BDependencies%26rnum%3D1%26hl%3Dnl%26#doc_5b14599ade6a27fc before responding.

> --Reference Unique
> R(a) ル S(b) ≡∀a E R,∀R(a): ∃!b E S | ∃!S(b) | a=b
>
> Hope it does not get messed up in web format...

No, it comes through nicely. Received on Thu Mar 01 2007 - 20:06:41 CST

Original text of this message

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