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Re: one big tables vs. many smaller

From: Steffen Ramlow <nospam_at_gmx.net>
Date: Tue, 9 Apr 2002 14:04:03 +0200
Message-ID: <a8ul89$ut90s$1@ID-54600.news.dfncis.de>


ok, then it seems that the denormalized scheme will be ok, because data integrity is ensured

"Daniel A. Morgan" <damorgan_at_exesolutions.com> wrote in message news:3CB05CE8.BD0B7CA9_at_exesolutions.com...
> There are things that are far more important than performance in a
database: One
> of them is data integrity.
>
> One huge flat file may well outperform two or three tables with an
inner/outer
> join. But you can not guarantee data integrity?
>
> I sometimes denormalize for performance ... but only in response to an
actual
> performance issue ... one that comes to my attention from a specific
end-user
> complaint and where that complaint can not be dealt with my some other
means.
> But even then, only if I can absolutely guarantee that data integrity and
> security will not be compromised.
>
> Daniel Morgan
>
>
>
> Steffen Ramlow wrote:
>
> > huch - did i ever talked about normalization?
> >
> > i talked about (read) performance and possible problems when using the
> > DE-normalized design
> >
> > as i already said - i personally would _always_ use the normalized form,
but
> > i need hard facts against the denormalized form, that's why i posted the
> > question
> >
> > this is what i think:
> >
> > denormalized:
> >
> > pros:
> > better read performance coz no join is needed (is the join really to
> > expensive?)
> > cons:
> > the table becomes really big
> > -> maybe a performance hit
> > -> maintenance difficulties
> > many null values (what are the problems with them?)
> > other?
> >
> > what i wanted to know is, what others think about this - i don't wanted
to
> > hear such general statements like "this is not normalized", this was
clean
> > right from the beginning
> >
> > "Daniel Morgan" <damorgan_at_exesolutions.com> wrote in message
> > news:3CAE11DE.381CBABD_at_exesolutions.com...
> > > You just defeated your own argument in your statement. If there are
many
> > many
> > > null values you do not have a normalized schema.
> > >
> > > I don't say this to be insulting ... but it seems that you have not
> > studied data
> > > normalization. A normalized table should not be a sparse matrix. And
your
> > > arument with respect to the number of "sub" tables is equally not
relevant
> > in a
> > > properly normalized schema. It strikes me that things you are
considering
> > should
> > > never exist.
> > >
> > > Daniel Morgan
> > >
> > >
> > >
> > > Steffen Ramlow wrote:
> > >
> > > > "damorgan" <damorgan_at_exesolutions.com> wrote in message
> > > > news:3CAC87E3.387D6428_at_exesolutions.com...
> > > > > Much like other things in life ... size has nothing to do with it
...
> > it
> > > > is
> > > > > what you do with it that counts. The definition of a table should
be
> > based
> > > > on
> > > > > data normalization tempered by performance. If it belongs in one
table
> > ...
> > > > > stick it there. If not ... don't.
> > > >
> > > > if there would only be one or to tables "Sub" then i would out int
into
> > the
> > > > big table
> > > > but there are up to 10 "Sub" tables - thus a big tables with many
many
> > null
> > > > values
> > >
>
Received on Tue Apr 09 2002 - 07:04:03 CDT

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