Re: abnormal forms

From: x <>
Date: Thu, 13 Apr 2006 18:18:03 +0300
Message-ID: <e1lq28$pel$>

"paul c" <> wrote in message news:QHa%f.6021$WI1.5342_at_pd7tw2no...

> First, I have a presumption that two relations can express the same
> value in different ways, ie., via different descriptions or expressions.
> For example, most people are familiar with the axiomatic attitude
> that different writings of attribute/column order don't change anything
> material.
> The first question is, is there anything axiomatic about an sva
> (single-valued attributes) relation when compared to an rva relation
> that has the same attributes?

> For example, (using ttm-style braces and for convenience omitting type
> names), is a SUPP{S#} relation logically the same value as a SUPP{{S#}}
> relation that is (somehow) constrained to have only one tuple? (not to
> be confused with one that somehow allows multiple tuples).

They are the same if they are the same :-) Received on Thu Apr 13 2006 - 17:18:03 CEST

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