Re: Question on Structuring Product Attributes

On 2011-10-19, Derek Asirvadem <derek.asirvadem_at_gmail.com> wrote:
> On Oct 17, 10:05?pm, Eric <e..._at_deptj.eu> wrote:
>>
>> It's sort-of fun to watch two people who don't know enough trying to
>> have an argument.
>
> It is even more fun to watch someone on the sidelines, who is not
> party to the argument, picking up clauses and examining them in
> isolation.

A private argument, on Usenet? Whatever next? And if a clause is all I
want to comment on, why should I not pick it out? There is no isolation,
everybody has read, or can read, the rest of the thread.

>> What on earth is "and have them in a visible column, non-pointer, form"
>> supposed to mean?
>
> Let me spell it out for you:
> - I was not posting a new thread (I would have used proper terms).
> - As I detailed to Jonathan, I was not writing a fully qualified
> thesis (if you are expecting that, you will find it lacking)
> - I was posting a response to Celko's thread. That defines the
> context.
> - Celko was playing "slippery fish", to avoid dealing with specific
> problems that I identified (check the whole thread)
> - In an attempt to prevent the slipperiness, I used Celko's terms.
> - As it progressed, I used further terms make distinctions, using his
> used terms as the base (I would not have used his terms, or my-terms-
> that-are-based-on-his-terms in a stand-alone article)

All you have spelled out is the context in which you wrote that, whereas what I wanted to know was what you meant by it and what is the alternative (since why mention it if there isn't one?).

>> All you can ever see of an index (apart from its
>> effect on query performance) is the list of columns indexed and some
>> vendor-dependent stuff usually about physical storage.
>
> Excellent, you seem to understand that correctly. So your question is
> either rhetorical or plain absurd.

No, see above.

> If you have an honest argument with me, just state it; if there is
> something you wish to clarify about one of my statements, ask a
> question.

Which is exactly what I did, but you provided no clarification whatsoever.

> But this picking and gnawing on the carcasses left, after
> others have feasted, is for the birds.

Now that's just rude.

>
>> Just to pick on one more thing:
>>
>> > - each PRIMARY KEY constraint builds an index
>> > - each UNIQUE constraint builds an index
>>
>> Not "builds", but "usually needs" :
>
> Correcting my English is petty. If you fancy yourself an editor, send
> me your CV, I will send you all my posts to edit, before I post.

I am _not_ correcting your English, I am questioning your meaning. Declaring a Primary Key does not necessarily cause an index to be built, though in most, if not all, current SQL-based systems, it requires that one exist. However there is no theoretical reason why this should be so, it is merely a readily available method that has been widely adopted. And yes, I have deliberately mentioned a theoretical possibility as part of my argument, you have no right to tell me that I can't.

>> - nowhere is there a requirement that primary and unique keys be
>> ? implemented with an index
>
> Try reading the entire statement in context. You might draw a
> different conclusion.

Obviously not!

> If that is still confusing, try this: I did not say "there is a
> requirement..." so there is no point arguing against what I did not
> say. I am quite happy to address issues regarding what I have said
> (the thread is ready evidence). But I do not engage with isolated
> scraps. It might give the readers the idea that such isolated scraps
> have some credibility, or that bird-like behaviour is appropriate for
> functioning adults.

More rudeness.

I never claimed that you said so, it was merely a part of my argument. If you want to insist that a discussion should be only on your terms then you are obviously not sure you can win without this. And, of course, you can't make rules of discussion here.

>> - only one index is needed and there is nothing to prevent an SQL parser
>> being smart enough to realise this
>
> Marvellous. Identify which SQL does that (post evidence).

I don't know for certain that one exists. So what? I know that it is possible. Again, you can't make rules of discussion here.

> Until then your suggestion is possibility in the future, not a
> reality, which is what Celko posted (he did not say "sometime in the
> future, some SQL could ...", he posted "Here is how to do this
> [now] ..."), which I am arguing. I can simply state, no SQL does that
> [now]. The implication is "now", on Earth, not "ten years from now",
> not "if and when the vendors wake up and read Celko's post", not on
> the fourth moon of Jupiter.
>
>> - if the parser is not smart enough there may well be a way of
>> ? second-guessing it and still ending up with only one index.
>
> Feel free to post the method.

Create the table without declaring the keys, then create the appropriate index, then create the keys. No new indexes will be built.

I know this works in Oracle, because I do it frequently, and I am pretty sure it works in other products.

> Otherwise your suggestion is a yet
> another fantasy of could-bes and guesses. Just like Celko. Any
> examination reveals that his method is based on facilities that are
> not available now, as stated "do this", that the method might be
> useful at some point in the future, if and when some SQL vendor
> supplies the the underlying facility.
>
> My method is based on the here and now, in any SQL (I have
> specifically excluded the non-SQLs), on Earth.
>
>> And finally...
>>
>> > ... under the covers is not relevant ...
>>
>> True, but you don't always seem to understand where the covers are.
>
> Thanks for your opinion. I will make sure I give it the consideration
> it deserves, keeping in mind your demonstrated level of capability, in
> understanding technical matters, and your could-be, should-be,
> attitude to addressing present day reality.
>
> Should you wish to address any of the salient points in my post, a
> piece of meat, rather than a scrap, I might give your avian opinion
> more consideration.

You have failed to understand what I was saying. You have descended to insult. No doubt you will think you have "won". Enjoy your "victory".

Eric

-- 
ms fnd in a lbry