Re: A new proof of the superiority of set oriented approaches: numerical/time serie linear interpolation

On 30 avr, 18:08, "Brian Selzer" <b...@xxxxxxxxxxxxxxxxxxx> wrote:
"Cimode" <cim...@xxxxxxxxxxx> wrote in message

news:1177938789.949723.62480@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
[snip]

I am aware of that article but thank you for reminding it. It simply
a negation of previous work and has been demonstrated since as wrong
by Codd's disciples (Date, Darwen). The induction of NULL 3VL simply
breaks the POCW (Principle of Closed World) redefining the meaning of
a database as a collection of facts. I think of this tolerance as one
of Codd's errors.

In a closed world, there is no such thing as "missing information." Can you
provide a reference that states that Codd adopted the closed world
assumption? I've never read that he did, and in light of his views on
missing information, I would be surprised if he had. In an open world, the
focus is on what has been stated, and the contents of a database is a
collection of recorded facts, not a collection of all of the facts. D&D's
interpretation of the RM differs from Codd's in several substantive ways.
Aside from missing information, Codd never described a database as a
collection of relvars. In everything I've read, he has always referred to
database modifications as inserts, updates and deletes. This would follow,
since inserts, updates and deletes are statements that specify how what is
known about the universe now differs from what has already been recorded.
D&D's interpretation posits that insert, update and delete are simply
instances of relational assignment, blissfully ignoring their inherent
dependency on the current state.
The closed world is a precise concept identified by Date as a
consequence of RM 2VL. It is not just a figure of speech open for
subjective interpretation or redefinition. The closed world
assumption basically states that any proposition that can not be
validated by TRUE (existing tuple) should necessarily be validated by
FALSE(non existing tuple). The induction of a 3VL through NULL simply
breaks that principle because once neither can validate the
proposition by TRUE for existing tuples nor one can invalidate the
proposition for non existing records.

Hope this clarifies.

.

Relevant Pages

  • Re: Need to stop form from going to first record
    ... and deletes to use either SQL or stored procedures so that I ... can validate everything before I let it get into the back-end ... If you're going to manage all updates yourself, you really ought to be using ... MsgBox "Cannot update the database because ... ...
    (microsoft.public.access.formscoding)
  • Re: Size matters to some
    ... The underlying remote database connection ... physical layer is actually managing it all, the logical layer is forced to ... constraints as specified by developers. ... want to validate the information getting written. ...
    (comp.databases.pick)
  • Re: how to move location of default database???? plz!
    ... fine, cool about the database, it probably amounts to how much tagging one ... updates - i woulda rolled them all back. ... No recent version of Windows does ... well when you have less than about 50MB to 100MB of free space. ...
    (microsoft.public.windowsmedia.player)
  • Re: Update Sql Server 2000 database from the HP3000
    ... collects those updates via ODBC every 10 or so seconds. ... essentially update the SQL database at the same time as the main ... Authorised and regulated by the Financial Services Authority. ...
    (comp.sys.hp.mpe)
  • Re: Please help: Numeric class properties
    ... > that reflects a table in my database. ... I wish to validate the property values before writing them ... TextBox entry BEFORE you attempt to assign it anywhere? ... Function IsDigitsOnly(Value As String) As Boolean ...
    (microsoft.public.vb.general.discussion)