Steve Cooper <[log in to unmask]> wrote:

>My personal experience is getting a bit dated, but I repeatedly here
>sentiments
>that match my data: most people who keep denormalized  or redundant data in
>their databases live to regret it.  It is a common and recurring cause of
>programming errors, and a constant struggle to figure out why the data is out
>of sync and how to fix it.  I have heard, more than once, a database designer
>saying "Never again" to the denormalized question.  I understand the realities
>out there, and it is always tempting, but I thought I would pass on these
>words
>from folks who have been there, done that.


When discussing Client/Server approaches, there are two things to consider:

1) The "native mode" IMAGE-intrinsics answer (which does not require SQL,
ODBC, JDBC, etc... --  ADBC is ok because it provides a DIRECT link from a
Java-enabled client to the native-mode MAGE intrinsics :-)

2) The emulation-mode "SQL" answer (which, for all practical purposes,
requires some kind of ODBC-like layer between the client and the server).


The operative phrase in Jim's original question is "to make it easier for
the C/S application":

>Therm-O-Link <[log in to unmask]> wrote:
>
>Okay, we have Image data bases that we are exposing to the fun world
>of PC, client/server, and ODBC.  We are displaying data for the user
>that may include data from multiple data sets.  Is it better to have
>a "normalized" data base or to have redundant data in multiple data
>sets to make it easier for the C/S application?


So, an answer that makes sense for a native-mode IMAGE-intrinsics solution
may not make sense (from a performance viewpoint) for an SQL-bases solution.

Normalization means "Keep together those things that belong together and
keep apart those things that belong apart."

Who is to say what "belongs" together and what "belongs" apart?  A
particular state of "normalization" (or lack thereof) is neither good nor
bad: It's some kind of compromise that you reach between theoretical
consistency and practical performance.

For a timeless review of normalization issues, please see a paper that I
wrote about 13 years ago, called Database Dynamics:

http://www.adager.com/TechnicalPapersPDF/DatabaseDynamics.pdf (PDF format)

http://www.adager.com/TechnicalPapersHTML/DatabaseDynamics.html (HTML format)

Enjoy,






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|            r  |  Alfredo                     mailto:[log in to unmask]
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|        g      |  F. Alfredo Rego                       +1 208 726-9100
|      a        |  Manager, R & D Labs               Fax +1 208 726-2822
|    d          |  Adager Corporation
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