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

In message <u60wc.5736$mK.281_at_newssvr32.news.prodigy.com>, Eric Kaun <ekaun_at_yahoo.com> writes
>> 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.
>
>In what way does storing the invoice in a single file mean the business
>analysis is simpler? You still had to identify attributes, and then of
>course make sure the ordering of elements in the MV attributes is the same,
>and possibly dissect values into sub-values...

When I analyse our MV system at work, I think in terms of physical objects. I then decompose each physical object into normal form. I DON'T NEED to think about other objects while I'm decomposing the one in front of me.

We're in the progress of porting to MS SQL-Server. The data diagram is an ABSOLUTE NIGHTMARE! When I look at the table diagram it's an absolute spaghetti of links EVERYWHERE! I don't have a clue which tables model which physical object, the meaning of links isn't intuitive.

Trying to juggle hundreds of tables is far harder than keeping track of several tens of physical objects to which I can relate, even if each of those objects is then broken down logically into normal form.

The MV database layout imposes a grouping which helps me grasp the system complexity. While I can easily view the MV structure as equal to the relational structure, a true relational database does not give me the MV structure which appears much less complicated by virtue of appealing to the way I naturally view the world.

Take the invoice. From the MV point of view, I see it as a SINGLE object. It is *TRIVIAL* for the database itself to decompose that and present it, via ODBC, to a relational programmer who wouldn't even realise that the MV back-end viewed it as a single object.

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