Re: Guessing?

From: Bob Badour <>
Date: Sun, 25 May 2008 18:53:58 -0300
Message-ID: <4839dff8$0$4035$>

paul c wrote:

> Bob Badour wrote:

>> See POOD and the justifications for it. I think it safe to say at 
>> least some relational proponents might agree with the comment about 
>> mysticism or at least that Codd's opinion on the matter was not as 
>> conclusive as he might have thought.

> Would you say POOD is an upshot of the Information Principle?

I would say POOD is a direct response to the sorts of view updating problems discussed in the book excerpt you omitted this time.

> Or is just a design approach Date and McGoveran came up with to work
> around what they saw as an implementation problem?

It is a design principle for avoiding ambiguity in view updates.

> A corrolary of the IP might be that any contradictory information allows
> contradictory results. If so, that wouldn't worry me. I'm
> distinguishing here between information that we know versus the more
> abstract information that the dbms has, given a particular design, I'd
> say only what the dbms knows matters.

POOD is all about making sure the dbms knows what it needs to know. (Not that I like anthropomorphizing dbmses.) Received on Sun May 25 2008 - 23:53:58 CEST

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