Re: Order among child nodes present in an XML document.

Dear Murali Mani,

thank you for your comments on the XML Query Requirements document
(http://www.w3.org/TR/2000/WD-xmlquery-req-20000131).
The working group has discussed them and has come to the
following conclusions.

> Date: Tue, 21 Mar 2000 02:03:44 -0800 (PST)
> From: Murali Mani <mani@CS.UCLA.EDU>
> To: www-xml-query-comments@w3.org
> Message-ID: <Pine.SOL.4.10.10003210159001.29555-100000@panther.cs.ucla.edu>
> Subject: Order among child nodes present in an XML document.
>
> The initial requirements does not specify how to handle the order
> among child nodes which is implied in the XML document. From my personal
> opinion, this order among child nodes is significant information, and
> should be captured in the XML data model. For query purposes, in the
> default case, the order among child nodes should be considered
> insignificant. But the query language should support constructs for
> querying on this order if the user wants to.
>
> Thanks - Murali.

This requirement is actually covered by 3.4.4 and 3.4.9
(a) "3.4.4 Hierarchy and Sequence
Queries MUST support operations on hierarchy and sequence of document
structures."
"Operations" include predicates (or equivalent mechanisms) which take
the sequential structure of  "nodes" (including in your terms
the order of "child-nodes") into account.

(b) "3.4.9 Structural Preservation
Queries MUST be able to preserve the relative hierarchy and sequence of input
document structures in query results."
This requirement implies that even with composed queries, XML Query
will be able to preserve the ordering information for tests in subsequent
queries.

In addition, requirement 3.3.1 "Reliance on XML Information Set"
implies that order of child-nodes is represented in the XML Query Data
Model.

Best regards,

Peter Fankhauser

Received on Thursday, 30 March 2000 10:13:37 UTC