Re: foundations of relational theory?

In article <BBnmb.21869$Fm2.11581_at_attbi_s04>, Marshall Spight <mspight_at_dnai.com> writes
>"Tony Gravagno" <g6q3x9lu53001_at_sneakemail.com.invalid> wrote in message
>news:7phbpv8g1h7m9g4csckol25ukoebjftvsv_at_4ax.com...
>> In my mind the answer to your questions is that a developer shouldn't
>> need to plan for every possible question that could be asked of
>> his/her database.
>
>Agreed.
>
>
>> If we create an application where it's function is
>> (now or perhaps in the future) to identify a parent based on the name
>> of one of her children, then the database should be constructed to
>> account for that eventuality.
>
>That doesn't sound so good to me. Having the schema be dependent
>on what applications we anticipate is a problem. Normalization
>makes it possible to have the schema be dependent solely on
>the relations among the data, and therefor be the correct schema
>for all possible applications. This gets you want you wanted
>in your first sentence: the developer doesn't need to plan for
>every possible query. He already knows he's done the right thing.
>
Yep. So we take the entity, normalise its attributes, and because of MV's abilities, we can store the entire normalised description of one entity instance in one RECORD.
>
>> In reality any good application
>> developer can predict the nature of most of the queries that will be
>> asked of the database within a specific business context.
>
>I'm sceptical of this claim.
>

Well, Tony used the word "most". And a good developer should know the *business* at which point, it's not difficult to guess what most of the queries will be.

The approach of relational is to make *all* queries *equally* easy (or hard). But why make the easy queries (the majority) harder, just to make the occasional hard query easier?
>
>> That
>> drasically limits the permutations, and allows the developer to create
>> only those structures necessary to support the application. When we
>> have needs to extend out of the box it's no problem to reformat data
>> into new tables, or simply create extended definitions that point to
>> existing data.
>
>Wouldn't you agree that it would be better to have a system
>whereby no changes to existing applications are necessary to
>accomodate new applications?
>

Yup. Couldn't agree more. But we MV'ers would argue that if you actually look at the real world, we seem to have achieved it more easily and cheaper than the relational people have :-)
>
>Marshall
>

Cheers,
Wol

-- 
Anthony W. Youngman - wol at thewolery dot demon dot co dot uk
Witches are curious by definition and inquisitive by nature. She moved in. "Let 
me through. I'm a nosey person.", she said, employing both elbows.
Maskerade : (c) 1995 Terry Pratchett