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Home -> Community -> Usenet -> comp.databases.theory -> Reflections of a beautiful mind... Fundamental principle: Separation of Concerns

Reflections of a beautiful mind... Fundamental principle: Separation of Concerns

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Sun, 23 Apr 2006 16:38:46 GMT
Message-ID: <q4O2g.64664$VV4.1224434@ursa-nb00s0.nbnet.nb.ca>


Returning to comp.databases.theory and the discussions here has prompted me to delve into the EWD archive at utexas. Like an inexhaustible jewel mine, the archive is full of great riches: gems reflecting a beautiful mind.

For instance, re-reading EWD 709:
http://www.cs.utexas.edu/users/EWD/transcriptions/EWD07xx/EWD709.html

I stumble across this gem:

"How well are we, for instance, able to separate the concern for
correctness from the concern for efficiency? Both concerns are so
"major", that I don't believe that significant progress will be possible
unless we manage to separate them completely."

I often speak of physical independence as a principle; however, the real   principle is the separation of concerns, of which physical independence is just one example as so eloquently stated by EWD above.

Similarly, logical independence separates the concern for correctness from the concern for convenience.

EWD lists three fundamental principles:

  1. separation of concerns and effective use of abstraction
  2. the design and use of notations, tailored to one's manipulative needs
  3. avoiding case analyses, in particular combinatorially exploding ones.

I wonder how many other principles distill down to just these three?

For instance, the third principle would seem to argue strongly against null and n-vl. Received on Sun Apr 23 2006 - 11:38:46 CDT

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