Re: In an RDBMS, what does "Data" mean?

In message <40bd0b99$0$561$e4fe514c_at_news.xs4all.nl>, mAsterdam <mAsterdam_at_vrijdag.org> writes
>Anthony W. Youngman wrote:
>
>mAsterdam writes
>>> This reduces the statement to
>>> "It was mathematically proven that it is simpler
>>> than the graph based approaches." and leaves the
>>> judgement to the reader/student. An improvement,
>>> but it still leaves the questions unanswered:
>>> simpler at what? etc.
>> And Occam's Razor (the Einstein version iirc) says "make things as
>>simple as possible, BUT NO SIMPLER".
>
>The examples given in Alfredo's links did a good job at shaving
>CODASYL's beard by providing the same and better
>results (for the "no simpler" part) from a much
>simpler construct. Did you read them?

Probably. And I probably didn't understand them.

All I'm trying to say is that simplicity as a goal in itself is a delusion.

And just because relational may be simpler than codasyl doesn't mean that it's a good thing. We have a real-world problem here ... look at the following mapping ...

real world <=> business analysis <=> database

What matters is the complexity (or simplicity) of the WHOLE SYSTEM. There's no point in simplifying the database, if the necessary increase in complexity of the business analysis totally negates it. By focussing on minimising the complexity of one part of the system, we make the system as a whole more complex. That will explain why Dawn's experience is that MV is more productive than relational - the simplicity of the relational database over MV simply pushes all the complexity into the business analysis side, turning that into a total nightmare.

Which is simpler - to model a single real world entity as a single database "table" as MV does (we can model an invoice in a single FILE), or as five or six relational tables? And don't forget - our FILE (should be) normalised, so we can access it just as if it were five or six relational tables ...

Yep. The database itself is more complex. But the business analysis is MUCH simpler, such that the total system complexity is a lot less.

Cheers,
Wol

-- 
Anthony W. Youngman - wol at thewolery dot demon dot co dot uk
HEX wondered how much he should tell the Wizards. He felt it would not be a
good idea to burden them with too much input. Hex always thought of his reports
as Lies-to-People.
The Science of Discworld : (c) Terry Pratchett 1999