Re: Beyond the 1600 columns limit on windows

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От Evandro's mailing lists (Please, don't send personal messages to this address)
Тема Re: Beyond the 1600 columns limit on windows
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Msg-id ffac56890511080901n20ed280ej4e988463ac0dbd4d@mail.gmail.com
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Ответ на Re: Beyond the 1600 columns limit on windows  (merlyn@stonehenge.com (Randal L. Schwartz))
Ответы Re: Beyond the 1600 columns limit on windows  (Richard Huxton <dev@archonet.com>)
Re: Beyond the 1600 columns limit on windows  ("John D. Burger" <john@mitre.org>)
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Sorry,
 
It has nothing to do with normalisation.  It is a program for scientific applications.
Data values are broken into column to allow multiple linear regression and multivariate regression trees computations.
 
Even SPSS the most well-known statistic sw uses the same approach and data structure that my software uses.
Probably I should use another data structure but would not be as eficient and practical as the one I use now.
 
Many thanks
-Evandro

 
On 08 Nov 2005 05:30:07 -0800, Randal L. Schwartz <merlyn@stonehenge.com> wrote:
>>>>> "Evandro's" == Evandro's mailing lists (Please, don't send personal messages to this address) < listasjr@gmail.com> writes:

[I would have replied to your personal address, but I'm not about
to copy it from a footer.]

Evandro's> I'm doing a PhD in data mining and I need more than 1600 columns. I got an
Evandro's> error message saying that I can not use more than 1600 columns.
Evandro's>  It is happening because I have to change categorical values to binary
Evandro's> creating new columns. Do you know if oracle can handle it?

/me boggles

You are doing a PhD in data mining, and you have a table that needs
more than 1600 columns?

/me gasps

What are they *teaching* these days?

If you have a design that has more than 20 or so columns, you're
probably already not normalizing properly.  There just aren't *that*
many attributes of a object before you should start factoring parts of
it out, even if it means creating some 1-1 tables.

In programming, if I ever see someone name a sequence of variables,
like "thing1" and "thing2", I know there's going to be trouble ahead,
because that should have been a different data structure.  Similarly,
I bet some of your columns are "foo1" and "foo2".  Signs of brokenness
in the design.

Or do you really have 1600 *different* attributes, none of which have
a number in their name?  That requires a serious amount of
creativity. :)

--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
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--
Evandro M Leite Jr
PhD Student & Software developer
University of Southampton, UK
Personal website: http://evandro.org
Academic website: http://www.soton.ac.uk/~evandro
Please, use Jr(at)evandro.org for personal messages

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