XQL Challenge (also, Design for Queryability)

Roger Costello costello at mitre.org
Mon Jul 5 15:23:31 BST 1999

Hi Folks,

I have created an XML document that contains Cellphone data.  
I have organized the data in this XML document similar to how
it might be organized in a database:

      - one subtree contains Cellphone hardware data (weight,
        battery, etc).
      - one subtree contains Cellphone feature data (caller id, one
        touch dialing, etc).
      - one subtree maps Cellphone hardware data to Cellphone feature
        data (in databases this would be called an "association

Why am I organizing the data in this fashion?  My hope is that
this approach will facilitate queryability of the data. That 
remains to be seen ...

Here's a sample query that I would like to perform:

"What features does the NOKIA 252 Cellphone have?"

If the data were in a database, such a query would be simple:

    SELECT features.name 
    FROM features, cellphones, cellphone-features
    WHERE features.id = cellphone-features.feature-id AND
          cellphone-features.cellphone-id = cellphones.id AND
          cellphones.brand = "NOKIA" AND
          cellphone.model = "252"

I am thinking (hoping) that I can perform a similar type of 
query using XQL.  Here's what I tried (among many other attempts):

= @id 
= 'NOKIA-252']

This XQL query doesn't work (it returns the empty set).

Below is sample data from my Cellphone XML document.  Any thoughts
on how to structure the XQL query?  /Roger

<?xml version="1.0"?>
        <model brand="NOKIA" name="252" technology="analog"
            <dimension units="inches">
                <height>6 5/8</height>
                <width>1 7/8</width>
            <weight units="ounces">6</weight>
            <battery type="nickel-cadmium">1100 mAh</battery>
            <talk-time units="minutes">132</talk-time>
            <standby-time units="hours">32</standby-time>
            <price currency="$US" with-contract="false">400</price>
            <price currency="$US" with-contract="true">180</price>
        <Authentication id="Authentication"/>
        <BatteryStrengthIndicator id="BatteryStrengthIndicator"/>
        <AudibleKeypadControls id="AudibleKeypadControls"/>
        <DTMF-KeytoneSignalling id="DTMF-KeytoneSignalling"/>
        <StoresNamesAndNumbers id="StoresNamesAndNumbers"/>
        <OneTouchDialing id="OneTouchDialing"/>
        <CallerID id="CallerID"/>
        <cellphone-feature cellphone-idref="NOKIA-252"
        <cellphone-feature cellphone-idref="NOKIA-252"

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at ic.ac.uk
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1
To (un)subscribe, mailto:majordomo at ic.ac.uk the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo at ic.ac.uk the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa at ic.ac.uk)

More information about the Xml-dev mailing list