Re: Proposal: 6NF

"Brian Selzer" <brian_at_selzer-software.com> wrote in message news:85QTg.6549$TV3.5203_at_newssvr21.news.prodigy.com...
>
> "Roy Hann" <specially_at_processed.almost.meat> wrote in message
> news:P-Sdnd58Trp7GYLYnZ2dnUVZ8tGdnZ2d_at_pipex.net...
>> "David Portas" <REMOVE_BEFORE_REPLYING_dportas_at_acm.org> wrote in message
>> news:1159692483.421785.264660_at_c28g2000cwb.googlegroups.com...
>>> Brian Selzer wrote:
>>>>
>>>> The argument JOG made focused only on recording information, not
>>>> retrieving
>>>> it. Why would anyone abandon a sound mechanism that can significantly
>>>> reduce the computing capacity required to answer a query?
>>>
>>> Because your argument is merely an assumption based on what some
>>> systems of today are capable of.
>>
>> It's worse. His entire position is based on not knowing even what some
>> of today's products are already capable of. For example, he seems
>> unaware of the role of the optimizer.
>
> I understand fully the role of the optimizer.

So why did you object that I was depending on a "physical order" of tables?

> That's one of my points. If you arbitrarily split a table with a nullable
> column, then you're robbing the optimizer of possible execution plans.

There is no logical way to decide whether to represent information as a row, an attribute, or a relationship. I can choose anything that is sensible. Whatever I choose is going to eliminate some possible plans but it is also going to create others.

And let me repeat: I am not speculating that my approach works. I use it routinely and it works very well. I therefore don't care what plans the optimizer never got to consider and nor should anyone else.

> It may make sense to split a table, for example, removing non-key columns
> that are seldom used in queries into another table in order to boost the
> performance of all other queries. The point I'm trying to make is that the
> decision should not be arbitrary.

What is arbitrary about saying that an attribute which doesn't apply to one type of fact must necessarily belong to another? It is the inescapable conclusion. To suggest the opposite is not only arbitrary, it is capricious, counterproductive, and misleading. If it weren't so tiresomely familiar it's bizarreness would be blindingly obvious.

Roy Received on Sun Oct 01 2006 - 17:01:13 CEST