Re: a union is always a join!

From: Walter Mitty <>
Date: Mon, 23 Mar 2009 08:08:06 GMT
Message-ID: <GrHxl.1596$>

"paul c" <> wrote in message news:oBAxl.19125$PH1.584_at_edtnps82...

> Brian Selzer wrote:

>> "Walter Mitty" <> wrote in message
>> news:R7qxl.1720$
>>> "Brian Selzer" <> wrote in message 
>>> news:50qxl.22730$
>>>> least not algebraic differences.  Once one admits that there are things 
>>>> in the universe of discourse that can appear different at different 
>>>> times, the semantics of insert, update and delete become clear: insert 
>>>> describes the beginning of the path that something travels through 
>>>> time, updates describe milestones along the path that mark changes in 
>>>> appearance, and delete describes the end of the path.  So a transition 
>>>> consisting of a delete and an insert that has no apparent effect on the 
>>>> database makes perfect sense because it describes the end of one thing 
>>>> and the beginning of another.
>>> This is mysticism.

>> What is your definition of mysticism? According to Webster, mysticism is
>> either

>> 1: the experience of mystical union or direct communion with ultimate
>> reality reported by mystics
>> 2: the belief that direct knowledge of God, spiritual truth, or ultimate
>> reality can be attained through subjective experience (as intuition or
>> insight)
>> 3a : vague speculation : a belief without sound basis b : a theory
>> postulating the possibility of direct and intuitive acquisition of
>> ineffable knowledge or power

>> My argument has nothing to do with a mystical union or direct
>> communication with ultimate reality, does not even refer to God,
>> spiritual truth or ultimate reality, nor does it concern the acquisition
>> of ineffable knowledge or power. I don't think there is anything vague
>> about my argument, and it is based upon the premise that there are things
>> in the universe of discourse that can appear different at different
>> times. I personally think that premise is reasonable. If you don't,
>> then I would like to hear your argument.
> (Pardon me for jumping in, ha ha, I should know better than to fall for 
> these flights of fancy, I guess I'm just a sucker for alternative 
> interpretations of the RM but I don't feel too guilty about that when even 
> the big guns are still debating some nuances.)
> Come on, this is a very unreasonable thing to ask of Walter (or any of the 
> few posters here nowadays), given what you wrote.  Eg., things that appear 
> different from what they are, not to mention time travel!

Actually, definition 3b (above) is pretty much on target with regard to this discussion.

Consider the last few exchanges between Brian and Tegiri.

Tegiri opined as to how an update is essentially the same thing as a delete followed by an insert. An eminently reasonable proposition, given that any delta in a database that can be caused by an update can also be caused by a suitable delete followed by a suitable insert. As a side note, the constraints on the database might be violated between the delete and the insert, but that's a digression.

Tegiri also offered up the delete and insert that exactly reverse each other as an exceptional case, because the delta in the database, in this case, is no diefference at all.

Brian jumped in on this case, and offered the opinion that a delete followed by an insert represnts the destruction of a thing in the UofD followed by the creation of a new thing in the UofD. In the case of an insert that ia followed by a reversing insert, it means, according to Brian, that something in the UofD has been destroyed, and replaced by an exact replica. This reminds me of an old Steve Wright joke, but that's another digression.

In any event, the idea that something real can happen in the UofD and the resulting difference in the database is no difference at all, fits awfully well with "ineffable knowledge, intuitively acquired". If you look at a database at one time, and then look at the database a little while later, and there's no difference, how do you know that everything in the UofD hasn't been destroyed, and replaced by an exact replica? You don't, according to Brian.

If Brian knows such a thing, it doesn't come from studying the data. It comes from ineffable knowledge, intuitively acquired. It's mystic crystal revelation, and the mind's true liberation. Received on Mon Mar 23 2009 - 09:08:06 CET

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