"Eric Kaun" <ekaun_at_yahoo.com> wrote in message
news:ejl1c.55384$GT6.254_at_newssvr33.news.prodigy.com...
> "Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message
> news:c1lhip$8lb$1_at_news.netins.net...
> > "Eric Kaun" <ekaun_at_yahoo.com> wrote in message
> > news:k6r%b.50112$LX2.42031_at_newssvr33.news.prodigy.com...
> > > As an aside in this discussion, I've seen "multivalued" defined 2
> > different
> > > ways in explanations of relational (some of which are really bad).
> > >
> > > 1. Where attribute A can hold a list of values (type LIST)
> > > 2. Where there are attributes A1, A2, A3, A4 (for example), all of the
> > same
> > > type and meaning. For example, ADDR1, ADDR2, etc.
> > > [...]
> > > Does 1NF refer to both of these? If not, what's the proper terminology
> for
> > > each of these cases?
> >
> > Good question because it is likely clear to most data folks that 1,
which
> is
> > the one more often referred to as multivalued (there is a MultiValue
> > trademark associated with one such model) and is not permitted by the
> > relational model, is a much better strategy than 2, which is permitted.
>
> Agreed that 2 is awful, but option 3, the relational way, is better yet.
>
> > I don't think there are any theories related to data storage and
retrieval
> > that would suggest that 2 is good design, but relational data modeling
in
> > practice is much more likely than others to promote this poor approach
>
> Not really - even in SQL, those who do something like option 2 are
vilified
> and stoned in the town square. People keep doing it, but they're usually
> uneducated or lazy (since I see it done even with very simple data models
> where it's completely unnecessary).
I've only ever seen one really egregious use of multiple columns of
conceptually identical data, and ironically it was created by someone just
as ignorant and just as vociferous as Dawn. Perhaps, in five years I will
find myself cleaning up one of Dawn's messes just as I recently cleaned up
the other mess left by some ignoramus who years ago preferred to argue with
me than to learn anything useful.
Received on Wed Mar 03 2004 - 17:00:29 CST
