Re: A Normalization Question

"x" <x-false_at_yahoo.com> wrote in message news:40e5608c_at_post.usenet.com...
> **** Post for FREE via your newsreader at post.usenet.com ****
>
>
> "Alan" <alan_at_erols.com> wrote in message
> news:2kggoeF24agdU1_at_uni-berlin.de...
>
>
> > You could normalize to a higher NF to prevent storing the value of
either
> > attribute more than once. This is done is real estate databases to save
> > space:
>
> > STREETS
> > street_id
> > street_name
>
> > HOUSES
> > house_number
> > street_id
> > etc
>
> > The idea here is that the street_id will _usually_ take less space on
disk
> > than the street name, so it is not necessary to record the street name
for
> > each house- just the street id.
>
> No. The idea here is that you may need to know if a given street exists
and
> what houses are on it.

No. Almost every town as an Elm Street, Washington, etc. It is a rare street that doesn't already exist, along with every possible house number. I worked at a major Multiple Listing Service. I know why we did this. In this case, further normalization increased performance instead of decreasing it, and saved tons of space in the process.

>
>
>
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> *** Usenet.com - The #1 Usenet Newsgroup Service on The Planet! ***
> http://www.usenet.com
> Unlimited Download - 19 Seperate Servers - 90,000 groups - Uncensored
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Received on Sat Jul 03 2004 - 00:31:31 CEST