Re: MV Keys

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Tue, 07 Mar 2006 21:17:36 +0100
Message-ID: <440dea57$0$11073$e4fe514c@news.xs4all.nl>

Jon Heggland wrote:
>
> mAsterdam says...
>

>>Jon Heggland wrote:
>>
>>>dcressey says...
>>>
>>>>An alternative example would be:
>>>>Is (onions, mushrooms) equal to (mushrooms, onions)?
>>>>I bleieve I've aske this question several times.
>>>
>>>I think the answer is obvious: It is whatever we define it to be. We 
>>>just have to make the decision at some point.
>>
>>This is like choosing the right or the left side of the road.
>>You don't. You may choose the country where you are going to
>>drive, but that's it.

>
>
> I don't get this analogy at all. If I have a pizza database, and for
> some reason want to model "toppings" as a single attribute, I will use a
> list if I (or the pizza place I'm making it for) want the topping order
> to matter, and a set if I don't. Where does the national government
> enter into it?
>
> Or are you quibbling about the specific notation (parenthesis, commas)
> that was used in the example?

No, not at all, sorry If I gave that impression.

I really would like to have it this way:

       "I will use a list if I want the order
        to matter, and a set if I don't."

(pizza specifics skipped)
, but in reality I don't have it like that. In most environments either sets (RDBMS) or lists (XML, Pick) are heavily favoured.

Now this is c.d.t, not c.d.p, so one could say that in theory it's just a choice. OTOH I think that these environments have theoretical and cultural roots (RM, Ontologies, Documents) yet to be investigated in a unified way. Received on Tue Mar 07 2006 - 14:17:36 CST