Re: Define "flatten database" ?

"DA Morgan" <damorgan_at_x.washington.edu> wrote in message news:1106957734.316617_at_yasure...
> Alan wrote:
>
> > "Dawn M. Wolthuis" <dwolt_at_tincat-group.comREMOVE> wrote in message
> > news:ctdn9o$7sq$1_at_news.netins.net...
> >
> >>"DA Morgan" <damorgan_at_x.washington.edu> wrote in message
> >>news:1106859773.807419_at_yasure...
> >>
> >>>silversw2000_at_yahoo.com wrote:
> >>>
> >>>
> >>>>I had a database analyst interview yesterday on the phone, and the
> >>>>interviewer brought up the phrase: "I flattened the database".
> >>>>
> >>>>I did not obfuscate in replying to her thread, but was able to avoid
> >>>>having to know what she meant by that term.
> >>>>
> >>>>Can someone define "flatten database" for me, in 100 words or less (OK
> >>>>500 words is fine).
> >>>>
> >>>>Fred Z.
> >>>>
> >>>
> >>>Denormalize.
> >>
> >>I would guess "normalize" is more likely. If the source dbms permits
> >>non-1NF structures, then the term "flatten" is sometimes used to mean
that
> >>the data are put in1NF. Terms I might use as synonyms to "flatten" are
> >>"unnest", "explode", "normalize". It isn't quite the same as
normalizing,
> >>however, because the embedded lists are not placed in a separate
relation,
> >>but rather the "scalar" data are repeated in each row, while the list
has
> >>one value per row. Reasons to flatten the structure would include a
need
> >
> > to
> >
> >>use a SQL-92-based tool or pour the data into a single Excel worksheet.
> >>
> >>If the source dbms is a SQL-based product, then the user might still be
> >>dumping tag-delimited lists in as attribute values (we all know there
are
> >>people who do that, right?) or even using some non-1NF capabilities of
the
> >>particular RDBMS.
> >>
> >>Example:
> >>
> >>Start with:
> >>
> >>(12345,DeSmith,John,{jsmith_at_aol.com,JohnSmith_at_yahoo.com})
>
>>(23127,Meador,Beth,{beth_meador_at_msn.com,bmeador_at_hotmail.com,btm_at_ibm.org})
> >>
> >>Then flatten it to get:
> >>
> >>(12345,DeSmith,John,jsmith_at_aol.com)
> >>(12345,DeSmith,John,JohnSmith_at_yahoo.com)
> >>(23127,Meador,Beth,beth_meador_at_msn.com)
> >>(23127,Meador,Beth,bmeador_at_hotmail.com)
> >>(23127,Meador,Beth,btm_at_ibm.org)
> >>
> >>That's my best guess. --dawn
> >>
> >>
> >>>--
> >>>Daniel A. Morgan
> >>>University of Washington
> >>>damorgan_at_x.washington.edu
> >>>(replace 'x' with 'u' to respond)
> >>
> >>
> >
> > Dawn,
> >
> > Flattening is DEnormalizing. Period. You have it backwards and twisted.
It
> > could be called Neo-normalizing.
>
> Which part of reading comprehension did you miss? ;-)
>
> My one word response was "Denormalize." You will find up up just
> under the signature "Fred Z."
>
> So I'm not sure what it is you are responding to. And given that I
> teach the subject here at the university I think I have at least
> a basic knowledge thereof.
> --
> Daniel A. Morgan
> University of Washington
> damorgan_at_x.washington.edu
> (replace 'x' with 'u' to respond)

Geez, Dan, I was on your side. I was responding to Dawn's insitence that flattening was something other than denormalizing.. Received on Sat Jan 29 2005 - 03:05:10 CET