Re: variable column table

From: Paul Brewer <paul_at_paul.brewers.org.uk>
Date: Tue, 27 May 2003 21:28:24 +0100
Message-ID: <3ed3ca94_2@mk-nntp-1.news.uk.worldonline.com>

"Billy Verreynne" <vslabs_at_onwe.co.za> wrote in message news:bavlg0$rjt$1_at_ctb-nnrp2.saix.net...
> sybrandb_at_yahoo.com wrote:
>
> > Design a meta-system where you have one central table holding entities
> > and attributes. Currently don't have such a design at hand, but I have
> > seen it several times.
>
> You mean having one table with loads of columns?
>
> Then have a kind of dictionary table that says for entity type 1, col 1 is
> name, col 2 is colour and so on, while for entity type 2, col 1 is weight
> and col 2 is a description?
>
> Or do I have my mouth around the wrong end of the bottle?
>

Billy,

This is the kind of thing, yes.

But you're getting into 4th and 5th normal form. Design becomes aesthetically perfect, but real world performance goes down the plughole. IMHO it's good for 'user extensions to the application', but one needs to be careful.

Regards,
Paul Received on Tue May 27 2003 - 15:28:24 CDT