XML-QL

Robert Hanson rhanson at blast.net
Mon Aug 31 00:06:35 BST 1998


If you read the end of the spec on what the "wish list" is for the final
version of the spec, it mentions that like XSL, they want it to be XML
complient.  Undoubtedly, this means the the tag minimization will be tossed.

...and I agree that making the query language XML complient is of
importance.  Besides that, I thought it was very good and useful.

As a programmer though, I see a few ways on how it could be implemented...
1. Matches could be made on the XML as a stream., and return it as such.  So
you invoke a method on the Query control which asks for a single match.  The
application would that find the first match and return only that one. From
there you could recursively ask for the next match.

2. Return all of the matches in a single action as a single XML document.
The problem is that if the XML document is very long, this could take some
time (even days... if the XML document was big enough).

3. The query application acts as a search engine where is indexes the XML
documents before a query is made to increase the speed for the search.  This
could be combined with the interface I mentioned in #1 or #2.

Does anyone have any thoughts on this??  I was actually thinking about
creating a search application based on the current XML-QL note, and have not
decided on how the interface should work.  For those familiar with
Microsoft's ADO control, I was thinking something like that.  In which case,
the search would be return a single match for each call to the query engine.
The query would also be optimised based on what the options the user
wanted... like forward only, 1 match at a time (with a READ command, then a
MoveNext command) -OR- backwards and forwards ( involved caching previous
matches) -OR- forward, backward, first, last ( involves caching all of the
matches before allowing reads ).

Robert Hanson

-----Original Message-----
From: John E. Simpson <simpson at polaris.net>
To: xml-dev at ic.ac.uk <xml-dev at ic.ac.uk>
Date: Sunday, August 30, 1998 5:39 PM
Subject: Re: XML-QL


>[My first attempt at a reply doesn't seem to have gone through. Let's try
>this again....]
>
>At 03:53 PM 8/29/98 -0700, you wrote:
>>I just discovered the XML Query Language proposal at
>>http://www.w3.org/TR/NOTE-xml-ql/, and find it very interesting.  It looks
>>a lot like SQL, which could be handy, but also somewhat limiting.  What do
>>you'all think about it?
>
>Yes, it is interesting. The tag minimization (using the "</>" end tag) is
>very troublesome, though. Troublesome enough that I hope they either
>dispense with it altogether or stop referring to XML-QL queries as though
>they were well-formed XML and adopt terminology such as "XML-like" instead.
>
>=================================================
>John E. Simpson
>simpson at flixml.org
>http://www.flixml.org
>Just XML - coming in September from Prentice-Hall
>
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