"Bob Badour" <bbadour (AT) pei (DOT) sympatico.ca> wrote

You might be able to come up with a shorter list, namely the lists of truly
meaningful terms
that have NOT been corrupted and perverted by would be followers..

"If you can bear to hear the truth you've spoken,
Twisted by knaves to make a trap for fools,
Or see the works you gave your life to, broken,
And stoop and build 'em up with worn out tools,"
--Kipling--

On Jul 23, 5:46*am, Hans Mayr <mayr1... (AT) gmx (DOT) de> wrote:
This is a valid aggregate: over all rows.

That is a different case, obviously.

I reread your last email and realized you raised some critical points
we never had a chance to exchange upon throughout past conversations.

discovered Codd's relation construct fact encoding scheme with the
strong bias to understand the mathematical refining process that would
have naturally led him to conclude that such construct would be
practical/optimized to formalize facts based of a universe of
discourse specific observation/implementation .

I was initially genuinely more interested in the mathematical refining
process than the construct itself since I considered the relational
model more of an application of abstraction than a truly abstract
reasonning. Naturally, I started looking for *Codd's math* in
previous work of his, particularly on the subject of celullar automata
(1968) written prior to the publishing of the relational model 1969
and 1971 papers. I had a hope to get a clearer understanding of the
mathematical universe of discourse that may have driven him to the
assumption that a relation construct could represent a effective
solution to information encoding.

While studying Codd's cellular automata work, involving the
establisment of deterministic predictability through algebra,
probabilism and set theory (you have not misread) , I quickly realized
that an effective encoding scheme to represent pairs of logical values
was at the heart some fundamental issues in the relational model. My
big deception however was that there was no clear definite link
between the two papers, that could explain the *why* on the choice of
relations as a formal optimized construct. I felt very frustrated
since I could find an explanation on the choice of relations (why not
another construct?).

Having that said, I started looking of relational model as a related
but independent work of Codd's but I kept in mind which math were used
priorly and which problems Codd had to solve. As far as domains are
concerned, it is true they somehow remained *off the radar* in
relational theory development and algebric scrutiny. It is reasonable
to assume that they were an initial etymological tool Codd used to
designate sets of values in a non naive way to distinguish them from
define the computing construct of relation in the context of
constraint specialization. Once the relational construct was defined,
a probably more computing significant construct, the relation, was
clarified and placed the interest more its possible applications
rather than the theory behind the construct.

Such phenomenon can be observed in all great discoveries: the capacity
to generate a new field of investigation driven by application but
somehow amnesic asto the process that brought the discovery .




constraints specialization.

guess is there will be a need for tens of people like Date to clarify
signficant portions of it. In such perspective, I agree that a domain
theory is more than ever necessary. I have now spent 1 decade trying
to clarify some aspects of it with a significantly better grasp of
some of Codd's motivation and writings.