Re: Maximum of Columns in one table (9i)

"Thomas Kellerer" <WVIJEVPANEHT_at_spammotel.com> wrote in message news:3j27ueFnsu6oU1_at_individual.net...
> On 06.07.2005 15:49 Paul wrote:
>
> >>So I could have:
> >>person,question_no,response
> >
> > Nice, neat 3 column table!
> >
> >>or
> >>person,q1response,q2response,....,q200response
> >
> > OK, at the risk of further exposing my ignorance here, what would be
> > the difference (in particular for the sort of query you mention, and
> > it's a good example) between having your 201 column table or having a
> > table with 1 column which was an array with 201 elements.
>
> Try to query the following information with both solutions and you'll
know:
>
> List all persons that answered yes to the first, no the second and yes to
the
> tenth question.
>
> Thomas

Like most everyone else here, I've been doing this stuff for a lot of years (over a couple of decades, designed thousands of tables and dozens of applications). "tall and thin" is almost always the best. Survey results is the one area I've found that doesn't fit the rule. After a lot of trial and error, I've given in and created some "short and fat" tables (80 to 200 columns). Not pretty, but it simply becomes easier to develop effective applications.

As Sybrand said earlier, "One could question whether an entity with more than 40-50 attributes has been properly normalized. Probably it hasn't." Probably.

My 2 cents worth
RH Received on Wed Jul 06 2005 - 10:40:15 CDT