Date: Sun, 25 May 2008 18:53:58 -0300
paul c 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