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From: Jeff Chapman <Jeff.Chapman@pervasive.com>
Date: Mon, 26 Feb 2001 15:26:08 -0600
Message-ID: <1B5B8075481CD41185BF00508B64ED961D72E0@ausmail4.aus.pervasive.com>
To: www-ql@w3.org
First and foremost, I really appreciate the work that's being done here.  I
really value any effort to improve the ease of XML development and XQuery
seems well on it's way to accomplish this.

In a recent reply to Evan Lenz, Jonathan Robie asserts that "the purpose of
FLWR expressions, ... is to provide general SQL-like functionality for joins
and declarative restructuring".  Is the charter of the XQuery WG to solve
the query problem for XML developers, or to make life easier for SQL
applications and SQL programmers.  To me, these seem like two different
problem domains.  However, XQuery seems to be more focused on the "SQL-like
functionality" issue.

IMHO, in our effort to make XQuery look familiar to SQL coders, we're
throwing the baby out with the bathwater.  Specifically, I'm deeply troubled
that an XQuery expression is not valid XML.  This will immediately cause
problems when I try to store XQuery documents into an XML repository.  This
should trigger a sense of Deja Vu.  Aren't we ignoring a painful lesson from
our immediate past.  When people realized the gravity of the situation
caused by DTDs not being valid XML, the W3C immediately began work on a
solution--XML Schemas.  Unfortunately, XML Developers are now left
scrambling to support two completely different schema definition mechanisms.
If you're an XML tool vendor then this will guarantee that customers will
pay for upgrades on a very frequent basis.  However, I would hope we would
recognize that this was a mistake and learn from it, instead of repeating
that mistake with an XQuery syntax that is not valid XML.  

Also, my hope is that we're actually going to solve the key problems which
make it really difficult to use XML for data-centric instead of
document-centric purposes--and I don't mean to make XML look more like SQL.
Toward that end, the lack of Update capabilities is a huge hole.  While I
value the improvements in ease of use, I question the decision to invest in
a SQL-like syntax that isn't even valid XML while completely avoiding the
critical "Update" issue.  Without this functionality, data repository
vendors and application developers will continue to be forced to invested
heavily in proprietary tactics that further fragment and isolate XML
developers into vendor-specific camps.  Clearly, this is something that the
W3C should not encourage, either explicitly or implicitly.

Jeff Chapman
Principal Web Architect
Pervasive Software
Jeff.Chapman@pervasive.com <mailto:Jeff.Chapman@pervasive.com> 
Received on Monday, 26 February 2001 16:28:27 UTC

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