Re: no names allowed, we serve types only

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Sun, 21 Feb 2010 19:40:58 -0400
Message-ID: <4b81c48d$0$12430$9a566e8b_at_news.aliant.net>



Tegiri Nenashi wrote:

> On Feb 21, 3:05 am, Jan Hidders <hidd..._at_gmail.com> wrote:
>

>>On 20 feb, 03:40, David BL <davi..._at_iinet.net.au> wrote:
>>... E.g. a relation has an attribute
>>
>>>containing circles and you must allow it to be addressed using either
>>>circle or ellipse.
>>
>>Indeed. But the header would contain only Ellipse, and all subtypes,
>>including Circle, would be implied. ...

>
> Ellipse-Circle example is unconvincing. Both are conic sections and it
> is natural to suggest that the design would greatly benefit from
> introducing a single class instead of many. The only objection is that
> certain methods being constrained to subtypes (such as Circle) might
> greatly benefit in performance.

What's the radius of an ellipse?

The differences are conceptual and logical not just physical. Received on Sun Feb 21 2010 - 17:40:58 CST

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