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Re: Working draft of XQuery

From: <aayad@us.ibm.com>
Date: Mon, 11 Jun 2001 09:36:31 -0700
To: www-ql@w3.org
Message-ID: <OF12770EDA.5E02E656-ON88256A68.005B02E6@almaden.ibm.com>

>  >Good! This is Subject: what I was hoping for :-)
> >I also hope that there will be only one type system for xquery and the
> >algebra.

>  Certainly. Since the algebra defines the type system for XQuery, the
> language can not have a separate type system.

> Jonathan

Regarding the subject of type systems, I am curious about the reason to be
concerned about strongly typing the algebra. From what I understand, the
algebra's job is to accurately and un-ambiguosly express the *operations*
and the outcome of a certain query. So, why complicate the algebra by a
type system. Clearly, nobody is going to use the algebra as its query
language, rather, it will merely be used to represent queries issued in an
XML query language (like XQuery). So, why not leave the task of
statically/dynamically checking the type of the inputs and outputs to the
query processors and focus in the algebra on the equivalence rules and
transformations. These are the important subject of the algebra *real*
users - the query optimizers.

best regards,
Received on Monday, 11 June 2001 12:36:40 UTC

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