The distinction between "is" and "has"

From: David Cressey <>
Date: Fri, 16 Nov 2007 13:02:54 GMT
Message-ID: <2yg%i.4024$ET.352_at_trndny03>

"David BL" <> wrote in message
> On Nov 16, 1:46 am, Marshall <> wrote:
> > So you can have two different attributes
> > with the same name.
> I assumed you meant that my definition was poor because it allowed two
> different attributes to have the same name.
> I admit I have no idea what you mean by distinguishing between "is"
> and "has".
> In natural language I'm comfortable with saying that an attribute
> *has* a name and domain, or with saying that an attribute *is* a
> composite of a name and domain, or an attribute *consists* of a name
> and domain. IMO all of these are equally valid informal
> descriptions.

David BL,

The distinction between "is" and "has" has been discussed in database literature for decades now. The particular things that have been said concerning this distinction may or may not be relevant to the ongoing development of what you have called a "work in progress".

I don't have a really good link to give you in this regard, and I hesitate to paraphrase what I remember, because that would probably side track the discussion. Hopefully, other regulars will contribute useful references. Perhaps D&D have something to say on the subject.

I changed the name of the topic in order to avoid hijacking your original topic.

Here's an example, to get things started: A car is a vehicle. A car has a steering wheel. Received on Fri Nov 16 2007 - 14:02:54 CET

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