Re: Which normal form is this violating?
From: Jan Hidders <hidders_at_uia.ua.ac.be>
Date: Tue, 30 Apr 2002 14:55:02 +0200
Message-ID: <3cce94b1$1_at_news.uia.ac.be>
Date: Tue, 30 Apr 2002 14:55:02 +0200
Message-ID: <3cce94b1$1_at_news.uia.ac.be>
"--CELKO--" <71062.1056_at_compuserve.com> wrote in message
news:c0d87ec0.0204291423.4e83e452_at_posting.google.com...
> >> No, the theory says no such thing. <<
>
> How many sets of Integers are there?
Uncountably many. :-)
> This is why Codd (and Date even
> more so) argued against redundant duplicates. Thus, a tuple has no
> repeated columns; a table (a set of tuples) has no dups in their
> model; a schema (a set of tables) has no dups in their model.
I have seen lots of formal definitions of a relational database and not one of them defined a schema as a set (as in set theory) of tables (or relations, to be more exact). Would you happen to have a reference for this?
- Jan Hidders