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Re: XQuery and DTD/Schema?

• To: xml-dev@l...
• Subject: Re: XQuery and DTD/Schema?
• From: Joe English <jenglish@f...>
• Date: Sun, 07 Jul 2002 13:30:46 -0700
• In-reply-to: <5.1.0.14.0.20020706134451.026cfd58@n...>
• References: <5.1.0.14.0.20020706134451.026cfd58@n...> <200207032047.g63Klik03022@l...> <200207032047.g63Klik03022@l...>

Jonathan Robie wrote:
> At 02:30 PM 7/3/2002 -0700, Joe English wrote:
>
> >I'd even question how relevant the efficiency issue is.
> >
> >XQuery is designed, principally, to do database queries.
> >In this context, it doesn't matter if you can take advantage
> >of type information to add two xs:integers in nanoseconds
> >instead of microseconds, when it takes milliseconds to retrieve
> >the data in the first place.
>
> Queries on large sets of data *do* need to be efficient - and when you want
> to be efficient, you try to avoid actually retrieving the data whenever
> possible. Reasoning about types statically is one of the ways we do this.


I still don't buy this argument.

Static typing can help optimize low-level operations that are
close to the machine (for instance this is why as a rule SML is
more efficient than Scheme), but languages that do heroic
optimizations -- APL, SQL, and Common Lisp for instance -- tend
to be dynamically typed.  Static typing is neither necessary
nor sufficient.

What optimization strategies does the XQuery type system enable?
Has anyone implemented, or even just designed, a database access
optimizer that takes advantage of it?


--Joe English

  jenglish@f...

• Follow-Ups:
  • RE: XQuery and DTD/Schema?
    • From: "Michael Kay" <michael.h.kay@n...>
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    • From: Dare Obasanjo <kpako@y...>

• References:
  • Re: XQuery and DTD/Schema?
    • From: Jonathan Robie <jonathan.robie@d...>
  • Re: XQuery and DTD/Schema?
    • From: Uche Ogbuji <uche.ogbuji@f...>

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