Re: Question on Structuring Product Attributes
Date: Sun, 17 Feb 2013 22:09:15 +0000
Message-ID: <slrnki2l8b.3g9.eric_at_teckel.deptj.eu>
On 2013-02-17, Rob <rmpsfdbs_at_gmail.com> wrote:
> On Saturday, February 16, 2013 4:20:01 PM UTC-7, paul c wrote:
>> On 14/02/2013 8:03 PM, James K. Lowden wrote: > SQL was intended, I'm >> sure you agree, to be a language for deriving logical inferences.
> [omitted text].
[more omitted text]
> Database technology has come a long way since the 1970s when SQL
> was initially specified, and relational DBMSs do alot more than
> report-writing. But to suggest that in the 1970s, the authors were
> interested in "logical inference" requires great poetic license compared
> to "replacing the report-writer capabilities of IMS", and feels like
> history rewritten.
To quote from Codd[1970]:
"The adoption of a relational model of data, as described above, permits the development of a universal data sublanguage based on an applied predicate calculus. A firstorder predicate calculus suffices if the collection of relations is in normal form."
I rather think there is a connection between "predicate calculus" and "logical inference", yes? So perhaps they should have been interested.
Not that I am denying that the report-writing mentality had a strong influence.
Eric
-- ms fnd in a lbryReceived on Sun Feb 17 2013 - 23:09:15 CET