"Invisible" <voi### [at] devnull> wrote in message
news:47596a5f$1@news.povray.org...

> True. But finding out 2 weeks ago would have been even better, no?

The ideal would have been finding out at design time. But is wishes were
horses...

> Ah, but can your boss actually do anything about this mess? That's the
> crucial question... ;-)

He can't stop it going in, it's too late and too many people have been
promised, etc, etc. IT's getting a bad rep for late delivery as is.

He is middle-upper management and he has enough authority to demand a
redesign (which he has) and to decide who does that (which he has) and to
'suggest' an examination of the way the developers work, to ensure this
doesn't happen again.

I foresee a lot of meeting next week.

> Yeah, cos after all, it's not like normal form is *important* or
> anything, is it?
>
> *weeps softly in the corner*

To C# developers it probably isn't, just as the patterns for app design
aren't that important to me. But in that case, they should keep their
fingers out of the DBs

> By the way... what *is* 4th normal form?

It's one I've seldom come across and doesn't apply often. Has to do with
multiple unrelated dependent attributes in a table.

Say we're writing a teaching management system. We need to store what
languages a teacher speaks and what courses they teach. We come up with
something like this

Teacher  Language  Course
Mr X      English      Account 1
Mr X      French      Account 1
Mr X      English      Ethics 1
Mr X      French      Ethics 1
Mrs S     English      Maths 1
Mrs S     English      Maths 2
Miss Z    English      History 1
Miss Z    German    History 1

It is in B-C normal form, however if we needed to indicate that Miss Z
starts teaching Archaeology 1, we need to add 2 rows.
4th normal form indicates that the two attributes should be split out into
selerate tables, so that there's one table that has the teacher's languages
and one that has the courses they teach.

That said, if the table stored the courses that the teacher offers and the
language that they are offered in, the above table would not be in violation
of 4th normal form.

Wiki has (as usual) a section on it
http://en.wikipedia.org/wiki/Fourth_normal_form

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