Re: Proposal: 6NF

From: David Cressey <dcressey_at_verizon.net>
Date: Wed, 18 Oct 2006 10:27:46 GMT
Message-ID: <CknZg.4747$5v5.3022@trndny08>

"paul c" <toledobythesea_at_oohay.ac> wrote in message news:g2iZg.155655$5R2.60964_at_pd7urf3no...
> David Cressey wrote:
> > "Tony D" <tonyisyourpal_at_netscape.net> wrote in message
> > news:1161090234.533844.46810_at_k70g2000cwa.googlegroups.com...
> >> paul c wrote:
> >>
> >>> Still, the bulk of the apps I've seen
> >>> don't need that extended type support ...
> >> I couldn't disagree with this observation more strongly. Without a rich
> >> type system, we can't talk about the right things (attributes). If we
> >> can't talk about the right things, we can't reasonably expect to
> >> construct proper statements (relations). As well to make assertions
> >> about horse racing by discussing camels :) And to have a rich type
> >> system, we'd better make sure the underpinnings are at least consistent
> >> and preferably correct ;)
> >
> > It seems to me that it's possible to talk about the right things with a
rich
> > domain system,
> > even if lacking a rich type system. It also seems to me that user
defined
> > domains are not the same thing as additional types.
> >
> >
> >
> >

>
>

> PMFJI, when it comes to a dbms engine, I don't know the difference
> between a type and a domain.

>
In the context of a dbms engine, a type would be the built in datatypes that the engine supports, like INTGER, DECIMAL, CHAR, and DATE, and also the builtin functions and operations, like "+" or "weekday(x)".

A domain would be what you get when you say CREATE DOMAIN. It's a set, but it has no functions and operations other than the ones it inherits from the data type it is based on.

Does this make sense?

> p
Received on Wed Oct 18 2006 - 05:27:46 CDT