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Re: XML storing and management

From: JOG <jog_at_cs.nott.ac.uk>
Date: Thu, 27 Sep 2007 16:11:53 -0700
Message-ID: <1190934713.790491.280920@57g2000hsv.googlegroups.com>


On Sep 27, 5:44 pm, Jan Hidders <hidd..._at_gmail.com> wrote:
> On 27 sep, 16:27, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
>
> > Jan Hidders wrote:
> > > On 27 sep, 02:19, JOG <j..._at_cs.nott.ac.uk> wrote:
>
> > >>Ok, so why is it exactly cdt, despite the inherent flaws of a
> > >>hierarchical model such as XML, it has seen such widespread uptake?
>
> > > It's all hype, of course.
>
> > > Btw., what fundamental flaws?
>
> > Well, let's see... How about we start with: "The inability to re-order
> > the data without changing meaning and without destroying information." ?
>
> "Hierarchical models such as XML" are not necessarily ordered-only
> data models. In fact most proposals for semistructured data models
> before XML weren't.

You make a good point because from what I can tell from the literature, XML has pretty much hijacked all previous work on "semistructured" data (Lore, etc).

But nervmind that - what, pray tell exactly is this "semi-structure" anyhow? I ask this question mischeviously of course, having done a lot of research on pinning down a definition, discovered that there is none, or at best it is recursive. Some definitions in peer-reviewed ACM papers are downright dreadful - "data that doesn't fit in a relational database"!?

At the moment "semi-structure" as a term it is academic flim-flam. Nonetheless I believe this can be remedied, and have been doing some work on it recently.

>
> But even in XML this is not a big problem. Whether reordering destroys
> information or not depends on your interpretation of the data. If you
> send me an XML document and in addition tell me that certain parts
> represent sets then I can reorder them without destroying any
> information. The fact that XML is an ordered data model only implies
> that it *might* destroy informaton, not that it *must*. There are ways
> to declare in languages such as XQuery that certain parts, or the
> whole tree, or certain final or intermediate results should be
> interpreted as unordered, so also that is not really a big or
> fundamental problem.
>
> Of course, I'm not claiming that it could not have been better. I'd
> personally prefer it if there had been a standardized way of
> indicating unorderedness and that this would have been taken into
> account in query languages such as XQuery. But the fact is that up to
> now neither the people that are using XQuery in practice nor the
> people that are implementing XQuery have been listing this as their
> prime concern. And you can theorize as much as you like, but it is
> practice that decides whether something is really a fundamental or
> inherent problem or not.
>
> -- Jan Hidders
Received on Thu Sep 27 2007 - 18:11:53 CDT

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