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Re: Hierarchical query

From: Jan Hidders <hidders_at_gmail.com>
Date: Thu, 14 Jun 2007 02:47:55 -0700
Message-ID: <1181814475.723433.274250@n15g2000prd.googlegroups.com>


On 14 jun, 01:39, Vadim Tropashko <vadimtro_inva..._at_yahoo.com> wrote:
> On Jun 13, 3:47 pm, Jan Hidders <hidd..._at_gmail.com> wrote:
> > Of course, all computation, including RDBMS and XML querying and
> > transformation, is ultimately just string manipulation. Doesn't mean
> > that Turing Machines are always the most appropriate formalism for
> > describing them, does it? :-)
>
> You seem to imply that language theory reduces to trivial string
> manipulation.

Trivial? You think that the string manipulations expressed by Turing Machines are trivial?

> I expected you to request clarification why a query is a
> language intersection; is there any nonvacuous idea behind this
> statement? And insist on demonstating that the reg exp method does
> work:-)

I though insisting that it cannot work would accomplish the same. But your explanation still does not seem complete. Also you are still a bit vague on what you are claiming. Are you saying that anything for which one would typically use XPath can be done just as well with regular expressions assuming that the tree is somehow encoded in a string? This is clearly not the case for the encoding you gave. Or are you going to extend that? Perhaps also extend the regular expressions a little? Or did you just have a particular query in mind? That would probably not be a very interesting observation. So which is it?

Received on Thu Jun 14 2007 - 04:47:55 CDT

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