Best way to design table to store attributes?

#11

On Jan 25, 3:57 am, Bob Badour <bbad... (AT) pei (DOT) sympatico.ca> wrote:

Quote:

paul c wrote:
patrick... (AT) yahoo (DOT) com wrote:

While the DATA in these tables could have a zillion states, thats like
saying that an ssn field has 10^9 states because it has nine
characters that can range from zero to nine.

Yes, exactly like that. One of my high school french teachers would have
reponded to that with "You have a fine grasp of the obvious." Except
elsewhere Patrick utterly fails to demonstrate any such grasp.

I suggest one stop to ponder that a billion seems like a large number
but it is infinitesimally small compared to 10^45, which is itself
infinitesimally small comparet to 10^90.

Yes, there may be many
many possible values, but simple payroll programs for example are not
burdened with a zillion states as either entire ranges of values are
handled identically, or the unneeded values are simply never entered
into storage.

That depends on the payroll program. ADP regularly handles on the order
of 10^7 social security numbers, and the IRS handles on the order of
10^8 or 10^9 of them--when one stops and considers that even
non-resident aliens like myself sometimes have one.

Nevertheless, 10^45 states is a vast number of states. It is on the
order of the mass of the sun in picograms. However, Carl's explanation
suggests the first thing anyone will do with that data is dimension
reduction.

Bob's 10^45 states argument appeared in his first response to Carl's
original post and in that post I can't see any suggestion that "the
first thing anyone will do is data reduction". Nevertheless, I don't
have a problem with Bob asking the question of whether it really makes
sense to record so many independent boolean attributes.

Bob needs to refine his apparent claim that an excessive number of
possible states suggest poor design. For example, a 1 mega-pixel 24
bpp image has about 10^(7 million) possible states.

#12

On Jan 24, 1:44*pm, patrick... (AT) yahoo (DOT) com wrote:

Quote:

Anyone else? Why are we worried about state here? Carl, if you're
still reading, why are you writing a state machine? Or are you?

You can say:

"it's a graph"

or

"it's a sparse matrix"

But the point is, it's a mapping from set A to set B.

And Bob's point is that there are other ways to model mappings,
especially the kind of sparse mapping associated with human
preferences among 150 choices, than as a dense matrix.

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Best way to design table to store attributes?

comp.databases.theory comp.databases.theory

Re: Best way to design table to store attributes? - 01-25-2009 , 07:22 PM

Re: Best way to design table to store attributes? - 01-27-2009 , 10:48 PM