# Re: Operationalize orthogonality

Date: Mon, 5 Jun 2006 15:18:13 +0300

Message-ID: <e6177v$3b3$1_at_nntp.aioe.org>

"Tony D" <tonyisyourpal_at_netscape.net> wrote in message
news:1149508866.617362.185540_at_u72g2000cwu.googlegroups.com...

*>
**> x wrote:
*

> > "Tony D" <tonyisyourpal_at_netscape.net> wrote in message

*> > news:1149504303.205324.83320_at_j55g2000cwa.googlegroups.com...
**> > >
**> > > x wrote:
**> > >
**> > > > How complicated! It would not be easyer to follow Mr. Codd advice ?
**> > > > Domains, not types.
**> >
**> > > And the difference between a domain and a type is what ? Precisely ?
**> > The "standard" answer would be "educate yourself". :-)
*

> Alternatively, you could attempt a non-standard answer ?

I did. Have you noticed the "" and the :-) ?

> > I don't know how "precisely" you want me to be.

> As precise as you need to be to point out what you believe the

*> difference between a domain and a type is.
*

It was precise enough ? I wondered if you asked for mathematical symbols, that's all.

> > I would say that my current understanding of this (because I have not

yet

> > read Codd's 1990 book - which I strongly recommend because I browsed it)

is

*> > that domains do not include any kind of operator.
*

> So, if domains include no operators, what can you do with them ?

Anything you want. For example you can define relations on them. Of course I excluded from the exclusion equality, membership and enumeration or something like these.

> In this context, I equate the terms domain and type - as mentioned in

*> the presentation pointed to elsewhere on this thread.
*

Sorry, I've forgoten about that. Good work. What I do not include in the domain (or type if you want to call it that way) are the operators like +, -, *,/, type conversions, etc. I think you first need a domain to be able to define a type - or viceversa :-)

<(I don't,

> however, equate classes with domains or types - principally because

*>(a) I'm not 100% clear on what a class is exactly,
*

I think you have been a member/participant of/in a class, so the percent is
greater than 0.

Can you give an approximation of the percent ? :-)

> (b) from what I do

*> understand about classes & objects, there is a dynamic element to them
**> that I wouldn't expect to find in a domain or type. I am open to
**> persuasion on these points.)
*

How about object = set of relations + operators (or object = db) ?

Sorry about these ":-)" Received on Mon Jun 05 2006 - 14:18:13 CEST