Re: The Null Problem is a Non-issue

On 2014-09-03, Derek Asirvadem <derek.asirvadem_at_gmail.com> wrote:
> On Wednesday, 3 September 2014 06:10:12 UTC+10, Eric wrote:

Patronising and unnecessary attempts to clarify quoting removed. Also, attribution line above restored to the single > that it should have.

>> Anyone who thinks that any level of multivalued logic is the answer to a >> problem of database design is wrong, even E.F.Codd when he did this.

> 1. Where, exactly, does Dr E F Codd make such a statement ?

Extending the database relational model to capture more meaning

Author: E. F. Codd IBM Research Lab, San Jose, CA

Published in:
· Journal
ACM Transactions on Database Systems (TODS) Volume 4 Issue 4, Dec. 1979
Pages 397-434
ACM New York, NY, USA

The above from
http://dl.acm.org/citation.cfm?id=320109&dl=ACM&coll=DL&CFID=553113776

More specifically, at the bottom of page 403, in section 2.3, there are truth tables with 3 rows and 3 columns, which are a pretty good indication of multi-valued logic. Indeed, the exact phrase "three-valued logic" appears above them.

BTW, for anyone who does not know, this is the RM/T paper.

Also, the book The Relational Model for Database Management: Version 2

Hardcover: 538 pages
Publisher: Addison Wesley Publishing Company (May 2000) Language: English
ISBN-10: 0201141922
ISBN-13: 978-0201141924 has a lot to say about it, including (page 387) under a heading of

23.5 Corrective Steps for DBMS Vendors

the section

23.5.3 Corrective Steps in Supporting Multi-Valued Logic

which includes references to two other Codd papers.

> 2. There is no "problem in database design". Any and all "problems"
> are completely resolved by formal education on the subject.

Completely? There is no perfect education, no perfect students, and can you prove that there is a perfect theory? In any case we are stuck with so many systems and databases created by the very inadequately educated. Can you be absolutely certain that some client will not hand you a business requirement that the methodology you apparently have will not be able to cope with?

> And please do not ask, for reasons already stated, I will not be providing
> that formal education here.

As I have already stated, I am not seeking any form of education from you!

Eric

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