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Re: CJ Date on Missing Information

From: Jonathan Leffler <jleffler_at_earthlink.net>
Date: Mon, 20 Mar 2006 05:34:28 GMT
Message-ID: <E9rTf.6657$Bj7.5524@newsread2.news.pas.earthlink.net>


Paul Mansour wrote:
> I've just read "The Default Values Approach to Missing Information" in
> Date's Database Writings 1989-1991. I've also noted that in the 8th
> edition of Date's main textbook, he refers to the "special values
> scheme' for handling missing information, and points to an article in
> Database Writings 1994-1997. I don't have the 94-97 book, though I am
> trying to track down a copy, and I'm curious to know if Date's view on
> handling missing information has changed since the 89-91 writings, or
> is it more or less the same. Any comments on this would be appreciated.

The 94-97 book has a set of 5 articles from DBP&D on 'Faults and Defaults' (Nov 1996 - Apr 1997), which elaborates on the other article.   I'm not certain, but my impression is that the scheme has been largely discarded. The issues with the expanded domains are certainly entirely non-trivial, IMO. See also Hugh Darwen's 'How to Handle Missing Information Without Using Nulls' (at http://www.thethirdmanifesto.com) and Fabian Pascal's 'The Final Null in the Coffin' (at http://www.dbdebunk.com - for a fee).

-- 
Jonathan Leffler                   #include <disclaimer.h>
Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com
Guardian of DBD::Informix v2005.02 -- http://dbi.perl.org/
Received on Sun Mar 19 2006 - 23:34:28 CST

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