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<title>XQuery Scripting Extension 1.0 Use Cases</title>
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<div class="head">
<p><a href="http://www.w3.org/"><img src=
"http://www.w3.org/Icons/w3c_home" alt="W3C" height="48" width=
"72" /></a></p>
<h1><a name="title" id="title"></a>XQuery Scripting Extension 1.0
Use Cases</h1>
<h2><a name="w3c-doctype" id="w3c-doctype"></a>W3C Working Draft 3
December 2008</h2>
<dl>
<dt>This version:</dt>
<dd><a href=
"http://www.w3.org/TR/2008/WD-xquery-sx-10-use-cases-20081203/">http://www.w3.org/TR/2008/WD-xquery-sx-10-use-cases-20081203/</a></dd>
<dt>Latest version:</dt>
<dd><a href=
"http://www.w3.org/TR/xquery-sx-10-use-cases/">http://www.w3.org/TR/xquery-sx-10-use-cases/</a></dd>
<dt>Previous version:</dt>
<dd><a href=
"http://www.w3.org/TR/2008/WD-xquery-sx-10-use-cases-20080328/">http://www.w3.org/TR/2008/WD-xquery-sx-10-use-cases-20080328/</a></dd>
<dt>Editor:</dt>
<dd><span><a href="http://snelson.org.uk/john">John
Snelson</a></span>, Oracle Corporation <a href=
"mailto:john.snelson@oracle.com"><john.snelson@oracle.com></a></dd>
</dl>
<p class="copyright"><a href=
"http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2008 <a href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup>
(<a href="http://www.csail.mit.edu/"><acronym title=
"Massachusetts Institute of Technology">MIT</acronym></a>, <a href=
"http://www.ercim.org/"><acronym title=
"European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>,
<a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved.
W3C <a href=
"http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
<a href=
"http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>
and <a href=
"http://www.w3.org/Consortium/Legal/copyright-documents">document
use</a> rules apply.</p>
</div>
<hr />
<div>
<h2><a name="abstract" id="abstract"></a>Abstract</h2>
<p>This document specifies usage scenarios for the XQuery Scripting
Extension.</p>
</div>
<div>
<h2><a name="status" id="status"></a>Status of this Document</h2>
<p><em>This section describes the status of this document at the
time of its publication. Other documents may supersede this
document. A list of current W3C publications and the latest
revision of this technical report can be found in the <a href=
"http://www.w3.org/TR/">W3C technical reports index</a> at
http://www.w3.org/TR/.</em></p>
<p>This is a <a href=
"http://www.w3.org/2005/10/Process-20051014/tr.html#maturity-levels">
Working Draft</a> as described in the <a href=
"http://www.w3.org/2004/02/Process-20040205/tr.html">Process
Document</a>. It has been developed by the W3C <a href=
"http://www.w3.org/XML/Query/">XML Query Working Group</a>, which
is part of the <a href="http://www.w3.org/XML/Activity">XML
Activity</a>. The Working Group expects to eventually publish this
document as a Working Group Note.</p>
<p>This document provides a number of use cases designed to
evaluate the language defined in <a href=
"http://www.w3.org/TR/xquery-sx-10/">XQuery Scripting Extension
1.0</a> at the time that it was issued as a Working Draft on 28
March 2008. Organizations and individuals should review this
document to ascertain whether or not adequate coverage of the
requirements is provided by these use cases.</p>
<p>This document incorporates changes made against the previous
publication of the Working Draft of 28 March 2008. Changes to this
document since the previous publication of the Working Draft are
detailed in <a href="#id-revisions-log"><b>B Revision
Log</b></a>.</p>
<p>Please report errors in this document using W3C's <a href=
"http://www.w3.org/Bugs/Public/">public Bugzilla system</a>
(instructions can be found at <a href=
"http://www.w3.org/XML/2005/04/qt-bugzilla">http://www.w3.org/XML/2005/04/qt-bugzilla</a>).
If access to that system is not feasible, you may send your
comments to the W3C XSLT/XPath/XQuery public comments mailing list,
<a href=
"mailto:public-qt-comments@w3.org">public-qt-comments@w3.org</a>.
It will be very helpful if you include the string “[SXUC]” in the
subject line of your report, whether made in Bugzilla or in email.
Please use multiple Bugzilla entries (or, if necessary, multiple
email messages) if you have more than one comment to make. Archives
of the comments and responses are available at <a href=
"http://lists.w3.org/Archives/Public/public-qt-comments/">http://lists.w3.org/Archives/Public/public-qt-comments/</a>.</p>
<p>Publication as a Working Draft does not imply endorsement by the
W3C Membership. This is a draft document and may be updated,
replaced or obsoleted by other documents at any time. It is
inappropriate to cite this document as other than work in
progress.</p>
<p>This document was produced by a group operating under the
<a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5
February 2004 W3C Patent Policy</a>. W3C maintains a <a href=
"http://www.w3.org/2004/01/pp-impl/18797/status#disclosures">public
list of any patent disclosures</a> made in connection with the
deliverables of the group; that page also includes instructions for
disclosing a patent. An individual who has actual knowledge of a
patent which the individual believes contains <a href=
"http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">
Essential Claim(s)</a> must disclose the information in accordance
with <a href=
"http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">
section 6 of the W3C Patent Policy</a>.</p>
</div>
<div class="toc">
<h2><a name="contents" id="contents"></a>Table of Contents</h2>
<p class="toc">1 <a href="#use-cases-for-xquery-sx">Use Cases for
XQuery Scripting Extension</a><br />
    1.1 <a href="#rdb">Use Case "R" - Scripting
Relational Data</a><br />
        1.1.1 <a href=
"#rdb-dtd">Document Type Definition (DTD)</a><br />
            1.1.1.1
<a href="#dtd-for-usres.xml">DTD for users.xml</a><br />
            1.1.1.2
<a href="#dtd-for-items.xml">DTD for items.xml</a><br />
            1.1.1.3
<a href="#dtd-for-bids.xml">DTD for bids.xml</a><br />
        1.1.2 <a href=
"#rdb-data">Input Data</a><br />
        1.1.3 <a href=
"#rdb-sx-results">Queries and Results</a><br />
            1.1.3.1
<a href="#rdb-sx-results-q1">Q1</a><br />
            1.1.3.2
<a href="#rdb-sx-results-q2">Q2</a><br />
            1.1.3.3
<a href="#rdb-sx-results-q3">Q3</a><br />
            1.1.3.4
<a href="#rdb-sx-results-q4">Q4</a><br />
    1.2 <a href="#xhtml">Use Case "XHTML" -
AJAX Scripting with XHTML</a><br />
        1.2.1 <a href=
"#xhtml-data">Input Data</a><br />
        1.2.2 <a href=
"#xhtml-sx-results">Queries and Results</a><br />
            1.2.2.1
<a href="#xhtml-sx-results-q1">Q1</a><br />
            1.2.2.2
<a href="#xhtml-sx-results-q2">Q2</a><br />
    1.3 <a href="#webservice">Use Case "WS" -
XQuery for Web Services</a><br />
        1.3.1 <a href=
"#webservice-data">Input Data</a><br />
        1.3.2 <a href=
"#webservice-sx-results">Queries and Results</a><br />
            1.3.2.1
<a href="#webservice-sx-results-q1">Q1</a><br />
            1.3.2.2
<a href="#webservice-sx-results-q2">Q2</a><br /></p>
<h3><a name="appendices" id="appendices"></a>Appendices</h3>
<p class="toc">A <a href="#references">Normative
References</a><br />
B <a href="#id-revisions-log">Revision Log</a>
(Non-Normative)<br />
    B.1 <a href="#id-log-pending">Changes in
internal WD</a><br /></p>
</div>
<hr />
<div class="body">
<div class="div1">
<h2><a name="use-cases-for-xquery-sx" id=
"use-cases-for-xquery-sx"></a>1 Use Cases for XQuery Scripting
Extension</h2>
<p>The use cases listed below were created by the <a href=
"http://www.w3.org/XML/Query/">XML Query Working Group</a> to
illustrate important applications for an XQuery scripting
extension.</p>
<div class="div2">
<h3><a name="rdb" id="rdb"></a>1.1 Use Case "R" - Scripting
Relational Data</h3>
<p>This use case is based on performing updates on the data used in
Use Case "R" from the <a href="#XQueryUseCases">[XML Query Use
Cases]</a>. The DTD and sample data from this Use Case are copied
below for convenience, and exactly match those found in the XQuery
Use Cases.</p>
<p>The data represents a relational database used by an online
auction. The auction maintains a USERS table containing information
on registered users, each identified by a unique userid, who can
either offer items for sale or bid on items. An ITEMS table lists
items currently or recently for sale, with the userid of the user
who offered each item. A BIDS table contains all bids on record,
keyed by the userid of the bidder and the item number of the item
to which the bid applies.</p>
<p>The three tables used by the online auction are below, with
their column-names indicated in parentheses.</p>
<div class="exampleInner">
<pre>
USERS ( USERID, NAME, RATING )
ITEMS ( ITEMNO, DESCRIPTION, OFFERED_BY,
START_DATE, END_DATE, RESERVE_PRICE )
BIDS ( USERID, ITEMNO, BID, BID_DATE )
</pre></div>
<div class="div3">
<h4><a name="rdb-dtd" id="rdb-dtd"></a>1.1.1 Document Type
Definition (DTD)</h4>
<p>This use case is based on three separate input documents named
users.xml, items.xml, and bids.xml. Each of the documents
represents one of the tables in the relational database described
above, using the following DTDs:</p>
<div class="div4">
<h5><a name="dtd-for-usres.xml" id="dtd-for-usres.xml"></a>1.1.1.1
DTD for users.xml</h5>
<div class="exampleInner">
<pre>
<!ELEMENT users (user_tuple*)>
<!ELEMENT user_tuple (userid, name, rating?)>
<!ELEMENT userid (#PCDATA)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT rating (#PCDATA)>
</pre></div>
</div>
<div class="div4">
<h5><a name="dtd-for-items.xml" id="dtd-for-items.xml"></a>1.1.1.2
DTD for items.xml</h5>
<div class="exampleInner">
<pre>
<!ELEMENT items (item_tuple*)>
<!ELEMENT item_tuple (itemno, description, offered_by,
start_date?, end_date?, reserve_price?)>
<!ELEMENT itemno (#PCDATA)>
<!ELEMENT description (#PCDATA)>
<!ELEMENT offered_by (#PCDATA)>
<!ELEMENT start_date (#PCDATA)>
<!ELEMENT end_date (#PCDATA)>
<!ELEMENT reserve_price (#PCDATA)>
</pre></div>
</div>
<div class="div4">
<h5><a name="dtd-for-bids.xml" id="dtd-for-bids.xml"></a>1.1.1.3
DTD for bids.xml</h5>
<div class="exampleInner">
<pre>
<!ELEMENT bids (bid_tuple*)>
<!ELEMENT bid_tuple (userid, itemno, bid, bid_date)>
<!ELEMENT userid (#PCDATA)>
<!ELEMENT itemno (#PCDATA)>
<!ELEMENT bid (#PCDATA)>
<!ELEMENT bid_date (#PCDATA)>
</pre></div>
</div>
</div>
<div class="div3">
<h4><a name="rdb-data" id="rdb-data"></a>1.1.2 Input Data</h4>
<p>Here is an abbreviated set of data showing the XML format of the
instances:</p>
<div class="exampleInner">
<pre>
<items>
<item_tuple>
<itemno>1001</itemno>
<description>Red Bicycle</description>
<offered_by>U01</offered_by>
<start_date>1999-01-05</start_date>
<end_date>1999-01-20</end_date>
<reserve_price>40</reserve_price>
</item_tuple>
<em> ... Snip ... </em>
</items>
<users>
<user_tuple>
<userid>U01</userid>
<name>Tom Jones</name>
<rating>B</rating>
</user_tuple>
<em> ... Snip ... </em>
</users>
<bids>
<bid_tuple>
<userid>U02</userid>
<itemno>1001</itemno>
<bid>35</bid>
<bid_date>1999-01-07</bid_date>
</bid_tuple>
<bid_tuple>
<em> ... Snip ... </em>
</bids>
</pre></div>
<p>The entire data set is represented by the following table:</p>
<table border="1" summary="Data set table">
<caption>USERS</caption>
<thead>
<tr>
<td>USERID</td>
<td>NAME</td>
<td>RATING</td>
</tr>
</thead>
<tbody>
<tr>
<td>U01</td>
<td>Tom Jones</td>
<td>B</td>
</tr>
<tr>
<td>U02</td>
<td>Mary Doe</td>
<td>A</td>
</tr>
<tr>
<td>U03</td>
<td>Dee Linquent</td>
<td>D</td>
</tr>
<tr>
<td>U04</td>
<td>Roger Smith</td>
<td>C</td>
</tr>
<tr>
<td>U05</td>
<td>Jack Sprat</td>
<td>B</td>
</tr>
<tr>
<td>U06</td>
<td>Rip Van Winkle</td>
<td>B</td>
</tr>
</tbody>
</table>
<table border="1" summary="Data set table">
<caption>ITEMS</caption>
<thead>
<tr>
<td>ITEMNO</td>
<td>DESCRIPTION</td>
<td>OFFERED_BY</td>
<td>START_DATE</td>
<td>END_DATE</td>
<td>RESERVE_PRICE</td>
</tr>
</thead>
<tbody>
<tr>
<td>1001</td>
<td>Red Bicycle</td>
<td>U01</td>
<td>1999-01-05</td>
<td>1999-01-20</td>
<td>40</td>
</tr>
<tr>
<td>1002</td>
<td>Motorcycle</td>
<td>U02</td>
<td>1999-02-11</td>
<td>1999-03-15</td>
<td>500</td>
</tr>
<tr>
<td>1003</td>
<td>Old Bicycle</td>
<td>U02</td>
<td>1999-01-10</td>
<td>1999-02-20</td>
<td>25</td>
</tr>
<tr>
<td>1004</td>
<td>Tricycle</td>
<td>U01</td>
<td>1999-02-25</td>
<td>1999-03-08</td>
<td>15</td>
</tr>
<tr>
<td>1005</td>
<td>Tennis Racket</td>
<td>U03</td>
<td>1999-03-19</td>
<td>1999-04-30</td>
<td>20</td>
</tr>
<tr>
<td>1006</td>
<td>Helicopter</td>
<td>U03</td>
<td>1999-05-05</td>
<td>1999-05-25</td>
<td>50000</td>
</tr>
<tr>
<td>1007</td>
<td>Racing Bicycle</td>
<td>U04</td>
<td>1999-01-20</td>
<td>1999-02-20</td>
<td>200</td>
</tr>
<tr>
<td>1008</td>
<td>Broken Bicycle</td>
<td>U01</td>
<td>1999-02-05</td>
<td>1999-03-06</td>
<td>25</td>
</tr>
</tbody>
</table>
<table border="1" summary="Data set table">
<caption>BIDS</caption>
<thead>
<tr>
<td>USERID</td>
<td>ITEMNO</td>
<td>BID</td>
<td>BID_DATE</td>
</tr>
</thead>
<tbody>
<tr>
<td>U02</td>
<td>1001</td>
<td>35</td>
<td>1999-01-07</td>
</tr>
<tr>
<td>U04</td>
<td>1001</td>
<td>40</td>
<td>1999-01-08</td>
</tr>
<tr>
<td>U02</td>
<td>1001</td>
<td>45</td>
<td>1999-01-11</td>
</tr>
<tr>
<td>U04</td>
<td>1001</td>
<td>50</td>
<td>1999-01-13</td>
</tr>
<tr>
<td>U02</td>
<td>1001</td>
<td>55</td>
<td>1999-01-15</td>
</tr>
<tr>
<td>U01</td>
<td>1002</td>
<td>400</td>
<td>1999-02-14</td>
</tr>
<tr>
<td>U02</td>
<td>1002</td>
<td>600</td>
<td>1999-02-16</td>
</tr>
<tr>
<td>U03</td>
<td>1002</td>
<td>800</td>
<td>1999-02-17</td>
</tr>
<tr>
<td>U04</td>
<td>1002</td>
<td>1000</td>
<td>1999-02-25</td>
</tr>
<tr>
<td>U02</td>
<td>1002</td>
<td>1200</td>
<td>1999-03-02</td>
</tr>
<tr>
<td>U04</td>
<td>1003</td>
<td>15</td>
<td>1999-01-22</td>
</tr>
<tr>
<td>U05</td>
<td>1003</td>
<td>20</td>
<td>1999-02-03</td>
</tr>
<tr>
<td>U01</td>
<td>1004</td>
<td>40</td>
<td>1999-03-05</td>
</tr>
<tr>
<td>U03</td>
<td>1007</td>
<td>175</td>
<td>1999-01-25</td>
</tr>
<tr>
<td>U05</td>
<td>1007</td>
<td>200</td>
<td>1999-02-08</td>
</tr>
<tr>
<td>U04</td>
<td>1007</td>
<td>225</td>
<td>1999-02-12</td>
</tr>
</tbody>
</table>
</div>
<div class="div3">
<h4><a name="rdb-sx-results" id="rdb-sx-results"></a>1.1.3 Queries
and Results</h4>
<div class="div4">
<h5><a name="rdb-sx-results-q1" id="rdb-sx-results-q1"></a>1.1.3.1
Q1</h5>
<p>Insert a new bid for Roger Smith on item 1002, adding 10% to the
best bid received so far for this item, and report back what bid
was just entered.</p>
<p><em>Solution in the XQuery Scripting Extension:</em></p>
<div class="exampleInner">
<pre>
let $uid := doc("users.xml")/users/user_tuple[name = "Roger Smith"]/userid
let $topbid := max(doc("bids.xml")/bids/bid_tuple[itemno = 1002]/bid)
let $newbid := $topbid * 1.1
return (
insert nodes
<bid_tuple>
<userid>{ data($uid) }</userid>
<itemno>1002</itemno>
<bid>{ $newbid }</bid>
<bid_date>1999-03-03</bid_date>
</bid_tuple>
into doc("bids.xml")/bids,
<new_bid>{ $newbid }</new_bid>
)
</pre></div>
<p><em>Expected Result:</em></p>
<p>The best bid for item 1002 had been at 1200, thus Roger's bid is
at 1320.</p>
<div class="exampleInner">
<pre>
<new_bid>1320</new_bid>
</pre></div>
<p><em>Expected resulting content of bids.xml:</em></p>
<div class="exampleInner">
<pre>
<bids>
<bid_tuple>
<userid>U02</userid>
<itemno>1001</itemno>
<bid>35</bid>
<bid_date>1999-01-07</bid_date>
</bid_tuple>
<em> ... Snip ... </em>
<bid_tuple>
<userid>U01</userid>
<itemno>1002</itemno>
<bid>400</bid>
<bid_date>1999-02-14</bid_date>
</bid_tuple>
<em> ... Snip ... </em>
<bid_tuple>
<userid>U04</userid>
<itemno>1007</itemno>
<bid>225</bid>
<bid_date>1999-02-12</bid_date>
</bid_tuple>
<em> ... Snip ... </em>
<bid_tuple>
<userid>U04</userid>
<itemno>1002</itemno>
<bid>1320</bid>
<bid_date>1999-03-03</bid_date>
</bid_tuple>
</bids>
</pre></div>
</div>
<div class="div4">
<h5><a name="rdb-sx-results-q2" id="rdb-sx-results-q2"></a>1.1.3.2
Q2</h5>
<p>Place a bid for Roger Smith on item 1007, adding 10% to the best
bid received so far on that item, but only if the bid amount does
not exceed a given limit. Otherwise return the current top bid.</p>
<p><em>Solution in the XQuery Scripting Extension:</em></p>
<div class="exampleInner">
<pre>
let $uid := doc("users.xml")/users/user_tuple[name = "Roger Smith"]/userid
let $topbid := max(doc("bids.xml")/bids/bid_tuple[itemno = 1007]/bid)
let $newbid := $topbid * 1.1
return
if($newbid <= 240) then (
insert nodes
<bid_tuple>
<userid>{ data($uid) }</userid>
<itemno>1002</itemno>
<bid>{ $newbid }</bid>
<bid_date>1999-03-03</bid_date>
</bid_tuple>
into doc("bids.xml")/bids,
<new_bid>{ $newbid }</new_bid>
) else (
<top_bid>{ $topbid }</top_bid>
)
</pre></div>
<p><em>Expected Result:</em></p>
<p>Adding 10% to the best bid on item 1007 would require a bid of
247.5, which is more than the allowed limit of 240. Thus, the
bids.xml document does not change.</p>
<div class="exampleInner">
<pre>
<top_bid>225</top_bid>
</pre></div>
</div>
<div class="div4">
<h5><a name="rdb-sx-results-q3" id="rdb-sx-results-q3"></a>1.1.3.3
Q3</h5>
<p>Erase user Dee Linquent and the corresponding associated items
and bids. Return a count of the items and bids deleted.</p>
<p><em>Solution in the XQuery Scripting Extension:</em></p>
<div class="exampleInner">
<pre>
let $user := doc("users.xml")/users/user_tuple[name = "Dee Linquent"]
let $items := doc("items.xml")/items/item_tuple[offered_by = $user/userid]
let $bids := doc("bids.xml")/bids/bid_tuple[userid = $user/userid]
return (
delete nodes ($user, $items, $bids),
<deleted>
<items>{ count($items) }</items>
<bids>{ count($bids) }</bids>
</deleted>
)
</pre></div>
<p><em>Expected Result:</em></p>
<div class="exampleInner">
<pre>
<deleted>
<items>2</items>
<bids>2</bids>
</deleted>
</pre></div>
<p><em>Expected resulting content of items.xml:</em></p>
<div class="exampleInner">
<pre>
<items>
<item_tuple>
<itemno>1001</itemno>
<description>Red Bicycle</description>
<offered_by>U01</offered_by>
<start_date>1999-01-05</start_date>
<end_date>1999-01-20</end_date>
<reserve_price>40</reserve_price>
</item_tuple>
<em> ... Snip ... </em>
<item_tuple>
<itemno>1004</itemno>
<description>Tricycle</description>
<offered_by>U01</offered_by>
<start_date>1999-02-25</start_date>
<end_date>1999-03-08</end_date>
<reserve_price>15</reserve_price>
</item_tuple>
<item_tuple>
<itemno>1007</itemno>
<description>Racing bicycle</description>
<offered_by>U04</offered_by>
<start_date>1999-01-20</start_date>
<end_date>1999-02-20</end_date>
<reserve_price>200</reserve_price>
</item_tuple>
<item_tuple>
<itemno>1008</itemno>
<description>Broken bicycle</description>
<offered_by>U01</offered_by>
<start_date>1999-02-05</start_date>
<end_date>1999-03-06</end_date>
<reserve_price>25</reserve_price>
</item_tuple>
</items>
</pre></div>
<p><em>Expected resulting content of users.xml:</em></p>
<div class="exampleInner">
<pre>
<users>
<user_tuple>
<userid>U01</userid>
<name>Tom Jones</name>
<rating>B</rating>
</user_tuple>
<user_tuple>
<userid>U02</userid>
<name>Mary Doe</name>
<rating>A</rating>
</user_tuple>
<user_tuple>
<userid>U04</userid>
<name>Roger Smith</name>
<rating>C</rating>
</user_tuple>
<em> ... Snip ... </em>
<user_tuple>
<userid>U06</userid>
<name>Rip Van Winkle</name>
<rating>B</rating>
</user_tuple>
</users>
</pre></div>
<p><em>Expected resulting content of bids.xml:</em></p>
<div class="exampleInner">
<pre>
<bids>
<bid_tuple>
<userid>U02</userid>
<itemno>1001</itemno>
<bid>35</bid>
<bid_date>1999-01-07</bid_date>
</bid_tuple>
<bid_tuple>
<userid>U04</userid>
<itemno>1001</itemno>
<bid>40</bid>
<bid_date>1999-01-08</bid_date>
</bid_tuple>
<em> ... Snip ... </em>
<bid_tuple>
<userid>U02</userid>
<itemno>1002</itemno>
<bid>600</bid>
<bid_date>1999-02-16</bid_date>
</bid_tuple>
<bid_tuple>
<userid>U04</userid>
<itemno>1002</itemno>
<bid>1000</bid>
<bid_date>1999-02-25</bid_date>
</bid_tuple>
<em> ... Snip ... </em>
<bid_tuple>
<userid>U04</userid>
<itemno>1007</itemno>
<bid>225</bid>
<bid_date>1999-02-12</bid_date>
</bid_tuple>
</bids>
</pre></div>
</div>
<div class="div4">
<h5><a name="rdb-sx-results-q4" id="rdb-sx-results-q4"></a>1.1.3.4
Q4</h5>
<p>Monitor the bidding on the helicopter. If Roger Smith does not
have the current highest bid, add a bid for him that is one higher
than the top bid, unless the bid amount exceeds a given limit. Stop
monitoring when the auction has finished.</p>
<p><em>Solution in the XQuery Scripting Extension:</em></p>
<table border="1" summary="Editorial note">
<tr>
<td align="left" valign="top" width="50%"><b>Editorial
note</b></td>
<td align="right" valign="top" width="50%">2008-01-25</td>
</tr>
<tr>
<td colspan="2" align="left" valign="top">A naive execution of this
query would form a busy loop waiting for the auction to end. This
is not very desirable, so it's possible an alternative solution
should be found.</td>
</tr>
</table>
<table border="1" summary="Editorial note">
<tr>
<td align="left" valign="top" width="50%"><b>Editorial
note</b></td>
<td align="right" valign="top" width="50%">2008-01-25</td>
</tr>
<tr>
<td colspan="2" align="left" valign="top">The fn:current-date()
function is defined by XQuery as <a href=
"http://www.w3.org/TR/xpath-functions/#stable">"stable"</a>. This
means that the query's current dateTime/date/time will not change
for the duration of the query. It needs to be decided if we intend
queries to be able to have a notion of time passing, possibly by
defining the "execution scope" differently for scripting.</td>
</tr>
</table>
<div class="exampleInner">
<pre>
declare variable $uid := doc("users.xml")/users/user_tuple
[name = "Roger Smith"]/userid;
declare variable $item := doc("items.xml")/items/item_tuple
[description = "Helicopter"];
declare variable $result :=
"Error: The auction has already ended or no bids were placed";
declare variable $maximumExceeded := false();
while(xs:date($item/end_date) >= fn:current-date() and not($maximumExceeded)) {
let $bids := doc("bids.xml")/bids/bid_tuple[itemno = $item/itemno]
let $topbid := max($bids/bid)
let $newbid = $topbid + 1
where $bids[bid = $topbid]/userid != $uid
return
if($newbid <= 60000) then (
insert nodes
<bid_tuple>
{ $uid, $item/itemno }
<bid>{ $newbid }</bid>
<bid_date>{ fn:current-date() }</bid_date>
</bid_tuple>
into doc("bids.xml")/bids;
set $result := concat("What a bargain! You got a helicopter for ",
$newbid);
) else (
set $result := "Bidding exceeded 60000";
set $maximumExceeded := true();
)
};
$result;
</pre></div>
<p><em>Expected Result:</em></p>
<p>Since this document was published after the end date for the
auction ("1999-05-25"), the while loop will never be executed.</p>
<div class="exampleInner">
<pre>
Error: The auction has already ended or no bids were placed
</pre></div>
</div>
</div>
</div>
<div class="div2">
<h3><a name="xhtml" id="xhtml"></a>1.2 Use Case "XHTML" - AJAX
Scripting with XHTML</h3>
<p>XQuery is ideally suited to manipulating the XML trees of XHTML.
This use case speculates that XQuery could be used in the way
Javascript is now, to modify an XHTML web page whilst it is being
displayed. In this way XQuery can be used to implement effects like
those commonly referred to by the acronym AJAX.</p>
<p>This use case deals with a web page that can be used to perform
a search in a book database. In all queries, there is an assumption
that the xhtml document is supplied as the context item.</p>
<div class="div3">
<h4><a name="xhtml-data" id="xhtml-data"></a>1.2.1 Input Data</h4>
<p>The starting state of the web page consists of only a simple
XHTML form.</p>
<div class="exampleInner">
<pre>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Book Search</title>
</head>
<body>
<form>
Book Name: <input type="text" id="txtBookName"/>
<input type="button" id="btnSend" value="Start Search"/>
</form>
</body>
</html>
</pre></div>
</div>
<div class="div3">
<h4><a name="xhtml-sx-results" id="xhtml-sx-results"></a>1.2.2
Queries and Results</h4>
<div class="div4">
<h5><a name="xhtml-sx-results-q1" id=
"xhtml-sx-results-q1"></a>1.2.2.1 Q1</h5>
<p>Write a script to act as an "onclick" event handler for the
"btnSend" form button. The script calls a web service to search for
the book entered by the user and retrieve detailed information for
the book. While the user is waiting for the web service the message
"Loading Book" is displayed. This message is later replaced with
the detailed information for the book.</p>
<p><em>Input web page:</em></p>
<p>The web browser has already updated the content of the form's
text input with the user's search string, "XQuery".</p>
<div class="exampleInner">
<pre>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Book Search</title>
</head>
<body>
<form>
Book Name: <input type="text" id="txtBookName">XQuery</input>
<input type="button" id="btnSend" value="Start Search"/>
</form>
</body>
</html>
</pre></div>
<p><em>Solution in the XQuery Scripting Extension:</em></p>
<p>The element that caused the event is supplied as an external
variable called $eventNode. The web service is called using the
external functions "book:search", and "book:get".</p>
<div class="exampleInner">
<pre>
declare namespace xhtml="http://www.w3.org/1999/xhtml";
declare namespace book="http://www.example.com/booksearch";
declare simple function book:search($name as xs:string) as element(book)* external;
declare simple function book:get($isbn as xs:string) as element(bookinfo) external;
declare variable $eventNode as element() external;
declare $searchResults := ();
insert node <xhtml:div>Loading Book</xhtml:div>
after /xhtml:html/xhtml:body/xhtml:form;
set $searchResults :=
book:search($eventNode/preceding-sibling::xhtml:input[1]);
if($searchResults) then (
replace node /xhtml:html/xhtml:body/xhtml:div
with <xhtml:div>{
book:get($searchResults[1]/isbn)/html/node()
}</xhtml:div>;
)
else (
replace node /xhtml:html/xhtml:body/xhtml:div
with <xhtml:div>No books found!</xhtml:div>;
)
</pre></div>
<p><em>Results returned to the query from the function call
book:search("XQuery"):</em></p>
<div class="exampleInner">
<pre>
<book>
<title>XQuery from the Experts: A Guide to the W3C XML Query Language</title>
<isbn>0321180607</isbn>
</book>
<book>
<title>XQuery: The XML Query Language</title>
<isbn>0321165810</isbn>
</book>
</pre></div>
<p><em>Results returned to the query from the function call
book:get("0321180607"):</em></p>
<div class="exampleInner">
<pre>
<bookinfo>
<title>XQuery from the Experts: A Guide to the W3C XML Query Language</title>
<isbn>0321180607</isbn>
<html>
<h2 xmlns="http://www.w3.org/1999/xhtml">XQuery from the Experts: A Guide to the W3C XML Query Language</h2>
ISBN: 0321180607
</html>
</bookinfo>
</pre></div>
<p><em>Expected intermediate content of the web page:</em></p>
<div class="exampleInner">
<pre>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Book Search</title>
</head>
<body>
<form>
Book Name: <input type="text" id="txtBookName">XQuery</input>
<input type="button" id="btnSend" value="Start Search"/>
</form>
<xhtml:div xmlns:xhtml="http://www.w3.org/1999/xhtml">Loading book</xhtml:div>
</body>
</html>
</pre></div>
<p><em>Expected resulting content of the web page:</em></p>
<div class="exampleInner">
<pre>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Book Search</title>
</head>
<body>
<form>
Book Name: <input type="text" id="txtBookName">XQuery</input>
<input type="button" id="btnSend" value="Start Search"/>
</form>
<xhtml:div xmlns:xhtml="http://www.w3.org/1999/xhtml">
<h2>XQuery from the Experts: A Guide to the W3C XML Query Language</h2>
ISBN: 0321180607
</xhtml:div>
</body>
</html>
</pre></div>
</div>
<div class="div4">
<h5><a name="xhtml-sx-results-q2" id=
"xhtml-sx-results-q2"></a>1.2.2.2 Q2</h5>
<p>Write a script to act as an "onclick" event handler for the
"btnSend" form button. The script calls a web service to search for
the book entered by the user, and uses an additional web service to
find which libraries have these books on the shelves. The
information received is displayed asynchronously as it arrives.</p>
<p><em>Input web page:</em></p>
<p>The web browser has already updated the content of the form's
text input with the user's search string, "XQuery".</p>
<div class="exampleInner">
<pre>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Book Search</title>
</head>
<body>
<form>
Book Name: <input type="text" id="txtBookName">XQuery</input>
<input type="button" id="btnSend" value="Start Search"/>
</form>
</body>
</html>
</pre></div>
<p><em>Solution in the XQuery Scripting Extension:</em></p>
<p>The element that caused the event is supplied as an external
variable called $eventNode. The web services are called using the
external functions "book:search", and "library:find".</p>
<div class="exampleInner">
<pre>
declare namespace xhtml="http://www.w3.org/1999/xhtml";
declare namespace book="http://www.example.com/booksearch";
declare namespace library="http://www.example.com/library";
declare simple function book:search($name as xs:string)
as element(book)* external;
declare simple function library:find($isbn as xs:string)
as element(library)* external;
declare variable $eventNode as element() external;
declare variable $table := ();
insert node <xhtml:div><xhtml:table/></xhtml:div>
after /xhtml:html/xhtml:body/xhtml:form;
set $table := //xhtml:table;
for $book in book:search($eventNode/preceding-sibling::xhtml:input[1])
return (
insert node
<xhtml:tr>
<xhtml:td>{data($book/title)}</xhtml:td>
<xhtml:td>{data($book/isbn)}</xhtml:td>
<xhtml:td/>
</xhtml:tr>
as last into $table;
);
for $row in $table/xhtml:tr
return (
replace value of node $row/xhtml:td[3]
with string-join(library:find($row/xhtml:td[2])/name, ", ");
);
</pre></div>
<p><em>Results returned to the query from the function call
book:search("XQuery"):</em></p>
<div class="exampleInner">
<pre>
<book>
<title>XQuery from the Experts: A Guide to the W3C XML Query Language</title>
<isbn>0321180607</isbn>
</book>
<book>
<title>XQuery: The XML Query Language</title>
<isbn>0321165810</isbn>
</book>
</pre></div>
<p><em>Results returned to the query from the function call
library:find("0321180607"):</em></p>
<div class="exampleInner">
<pre>
<library>
<name>Bodleian Library</name>
<url>http://www.bodley.ox.ac.uk/</url>
<lending>no</lending>
</library>
<library>
<name>Radcliffe Science Library</name>
<url>http://www.ouls.ox.ac.uk/rsl/</url>
<lending>yes</lending>
</library>
</pre></div>
<p><em>Results returned to the query from the function call
library:find("0321165810"):</em></p>
<div class="exampleInner">
<pre>
<library>
<name>Radcliffe Science Library</name>
<url>http://www.ouls.ox.ac.uk/rsl/</url>
<lending>yes</lending>
</library>
</pre></div>
<p><em>Expected resulting content of the web page:</em></p>
<p>The web page will be altered as the results are received from
the web services, but the final result will look like this.</p>
<div class="exampleInner">
<pre>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Book Search</title>
</head>
<body>
<form>
Book Name: <input type="text" id="txtBookName">XQuery</input>
<input type="button" id="btnSend" value="Start Search"/>
</form>
<xhtml:div xmlns:xhtml="http://www.w3.org/1999/xhtml">
<xhtml:table>
<xhtml:tr>
<xhtml:td>XQuery from the Experts: A Guide to the W3C XML Query Language</xhtml:td>
<xhtml:td>0321180607</xhtml:td>
<xhtml:td>Bodleian Library, Radcliffe Science Library</xhtml:td>
</xhtml:tr>
<xhtml:tr>
<xhtml:td>XQuery: The XML Query Language</xhtml:td>
<xhtml:td>0321165810</xhtml:td>
<xhtml:td>Radcliffe Science Library</xhtml:td>
</xhtml:tr>
</xhtml:table>
</xhtml:div>
</body>
</html>
</pre></div>
</div>
</div>
</div>
<div class="div2">
<h3><a name="webservice" id="webservice"></a>1.3 Use Case "WS" -
XQuery for Web Services</h3>
<p>This use case deals with the implementation of a REST based web
service, specifically a micro-blog.</p>
<div class="div3">
<h4><a name="webservice-data" id="webservice-data"></a>1.3.1 Input
Data</h4>
<p>The default collection contains a forest of micro blog
documents, one for each user. Initially the forest contains these
documents.</p>
<p><em>John's micro-blog:</em></p>
<div class="exampleInner">
<pre>
<micro-blog user="john">
<entry timestamp="2007-10-17T10:02:53+01:00">
<text>Still reading email...</text>
</entry>
<entry timestamp="2007-10-17T20:19:31+01:00">
<text>Writing XQuery Scripting Extension use cases (ideas, anyone?)</text>
</entry>
<entry timestamp="2007-10-18T00:43:02+01:00">
<text>Thinking of going to bed</text>
</entry>
</micro-blog>
</pre></div>
<p><em>Emily's micro-blog:</em></p>
<div class="exampleInner">
<pre>
<micro-blog user="emily">
<entry timestamp="2007-10-16T18:12:51+01:00">
<text>So how do you use a micro-blog?</text>
</entry>
<entry timestamp="2007-10-16T18:13:20+01:00">
<text>Ah, I see</text>
</entry>
<entry timestamp="2007-10-17T07:33:44+01:00">
<text>Morning, everybody!</text>
</entry>
</micro-blog>
</pre></div>
<p><em>A document containing the blog access log:</em></p>
<div class="exampleInner">
<pre>
<log>
</log>
</pre></div>
</div>
<div class="div3">
<h4><a name="webservice-sx-results" id=
"webservice-sx-results"></a>1.3.2 Queries and Results</h4>
<div class="div4">
<h5><a name="webservice-sx-results-q1" id=
"webservice-sx-results-q1"></a>1.3.2.1 Q1</h5>
<p>Process a request from John to add a blog entry, returning a
confirmation XHTML page.</p>
<p><em>The element representing the request:</em></p>
<div class="exampleInner">
<pre>
<request>
<method>POST</method>
<url>http://blog.example.com/john/add</url>
<param name="text">Making a post to my XQuery blog engine</param>
</request>
</pre></div>
<p><em>Solution in the XQuery Scripting Extension:</em></p>
<p>The request element is bound to the external variable
$request.</p>
<div class="exampleInner">
<pre>
declare variable $request as element(request) external;
declare simple function local:error($message)
{
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Error</title>
</head>
<body>
<h1>Error</h1>
<p>{ $message }</p>
</body>
</html>
};
if($request/method = "POST") then () else
exit with local:error(concat("You cannot use the ",
$request/method, " method with this URL."));
let $user := replace($request/url, "^http://.*/([^/]+)/add$", "$1")
let $blog := collection()/micro-blog[@user = $user]
return (
if($blog) then () else
exit with local:error("Unknown user");
insert node
<entry timestamp="{ current-dateTime() }">
<text>{ $request/param[@name = "text"] }</text>
</entry>
as last into $blog;
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Blog entry added for { $user }</title>
</head>
<body>
<h1>Blog entry added for { $user }</h1>
<p>{ $request/param[@name = "text"] }</p>
</body>
</html>;
);
</pre></div>
<p><em>Expected Result:</em></p>
<div class="exampleInner">
<pre>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Blog entry added for john</title>
</head>
<body>
<h1>Blog entry added for john</h1>
<p>Making a post to my XQuery blog engine</p>
</body>
</html>
</pre></div>
<p><em>Expected resulting content of John's micro-blog:</em></p>
<div class="exampleInner">
<pre>
<micro-blog user="john">
<entry timestamp="2007-10-17T10:02:53+01:00">
<text>Still reading email...</text>
</entry>
<entry timestamp="2007-10-17T20:19:31+01:00">
<text>Writing XQuery Scripting Extension use cases (ideas, anyone?)</text>
</entry>
<entry timestamp="2007-10-18T00:43:02+01:00">
<text>Thinking of going to bed</text>
</entry>
<entry timestamp="2007-10-18T08:53:9+01:00">
<text>Making a post to my XQuery blog engine</text>
</entry>
</micro-blog>
</pre></div>
</div>
<div class="div4">
<h5><a name="webservice-sx-results-q2" id=
"webservice-sx-results-q2"></a>1.3.2.2 Q2</h5>
<p>Process the same request from John, using a function to check
that "john" is a valid user name and to log the event.</p>
<p><em>The element representing the request:</em></p>
<div class="exampleInner">
<pre>
<request>
<method>POST</method>
<url>http://blog.example.com/john/add</url>
<param name="text">Making a post to my XQuery blog engine</param>
</request>
</pre></div>
<p><em>Solution in the XQuery Scripting Extension:</em></p>
<p>The request element is bound to the external variable
$request.</p>
<div class="exampleInner">
<pre>
declare variable $request as element(request) external;
declare sequential function local:check-user-and-log($username as xs:string)
as element(micro-blog)?
{
declare $entry as element() :=
<access-attempt>
<timestamp>{fn:current-dateTime()}</timestamp>
<user-name>{$username}</user-name>
<access-allowed/>
</access-attempt>;
declare $blog as element(micro-blog)? :=
collection()/micro-blog[@user = $username];
if($blog) then
replace value of node $entry/access-allowed with "Yes"
else
replace value of node $entry/access-allowed with "No";
insert node $entry as last into collection()/log;
exit with $blog;
}
declare simple function local:error($message)
{
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Error</title>
</head>
<body>
<h1>Error</h1>
<p>{ $message }</p>
</body>
</html>
};
if($request/method = "POST") then () else
exit with local:error(concat("You cannot use the ",
$request/method, " method with this URL."));
let $user := replace($request/url, "^http://.*/([^/]+)/add$", "$1")
let $blog := local:check-user-and-log($user)
return (
if($blog) then () else
exit with local:error("Unknown user");
insert node
<entry timestamp="{ current-dateTime() }">
<text>{ $request/param[@name = "text"] }</text>
</entry>
as last into $blog;
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Blog entry added for { $user }</title>
</head>
<body>
<h1>Blog entry added for { $user }</h1>
<p>{ $request/param[@name = "text"] }</p>
</body>
</html>;
);
</pre></div>
<p><em>Expected Result:</em></p>
<div class="exampleInner">
<pre>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Blog entry added for john</title>
</head>
<body>
<h1>Blog entry added for john</h1>
<p>Making a post to my XQuery blog engine</p>
</body>
</html>
</pre></div>
<p><em>Expected resulting content of John's micro-blog:</em></p>
<div class="exampleInner">
<pre>
<micro-blog user="john">
<entry timestamp="2007-10-17T10:02:53+01:00">
<text>Still reading email...</text>
</entry>
<entry timestamp="2007-10-17T20:19:31+01:00">
<text>Writing XQuery Scripting Extension use cases (ideas, anyone?)</text>
</entry>
<entry timestamp="2007-10-18T00:43:02+01:00">
<text>Thinking of going to bed</text>
</entry>
<entry timestamp="2007-10-18T08:53:9+01:00">
<text>Making a post to my XQuery blog engine</text>
</entry>
</micro-blog>
</pre></div>
<p><em>Expected resulting content of the log:</em></p>
<div class="exampleInner">
<pre>
<log>
<access-attempt>
<timestamp>2007-10-18T08:53:9+01:00</timestamp>
<user-name>john</user-name>
<access-allowed>Yes</access-allowed>
</access-attempt>
</log>
</pre></div>
</div>
</div>
</div>
</div>
</div>
<div class="back">
<div class="div1">
<h2><a name="references" id="references"></a>A Normative
References</h2>
<dl>
<dt class="label"><span><a name="xquery" id="xquery"></a>XQuery
1.0</span></dt>
<dd>
<div>World Wide Web Consortium. <em>XQuery 1.0: An XML Query
Language</em>. W3C Recommendation, 23 January 2007. See <a href=
"http://www.w3.org/TR/xquery/">http://www.w3.org/TR/xquery/</a>.</div>
</dd>
<dt class="label"><span><a name="XQueryUseCases" id=
"XQueryUseCases"></a>XML Query Use Cases</span></dt>
<dd>
<div>World Wide Web Consortium. <em>XML Query Use Cases</em>. W3C
Working Group Note, 23 March 2007. See <a href=
"http://www.w3.org/TR/xquery-use-cases/">http://www.w3.org/TR/xquery-use-cases/</a>.</div>
</dd>
<dt class="label"><span><a name="updatespec" id=
"updatespec"></a>XQuery Update Facility</span></dt>
<dd>
<div>World Wide Web Consortium. <em>XQuery Update Facility</em>.
W3C Working Draft, 28 August 2007. See <a href=
"http://www.w3.org/TR/xquery-update-10/">http://www.w3.org/TR/xquery-update-10/</a>.</div>
</dd>
<dt class="label"><span><a name="serequirements" id=
"serequirements"></a>XQuery Scripting Extension 1.0
Requirements</span></dt>
<dd>
<div>World Wide Web Consortium. <em>XQuery Scripting Extension 1.0
Requirements</em>. W3C Working Draft, 23 March 2007. See <a href=
"http://www.w3.org/TR/2007/WD-xquery-sx-10-requirements-20070323">http://www.w3.org/TR/2007/WD-xquery-sx-10-requirements-20070323</a>.</div>
</dd>
</dl>
</div>
<div class="div1">
<h2><a name="id-revisions-log" id="id-revisions-log"></a>B Revision
Log (Non-Normative)</h2>
<p>This log records the substantive changes that have been made to
this document . Minor editorial changes are not included in this
log.</p>
<div class="div2">
<h3><a name="id-log-pending" id="id-log-pending"></a>B.1 Changes in
internal WD</h3>
<ul>
<li>
<p>Added an editorial note detailing the problems with RDB Q4.</p>
</li>
<li>
<p>Added the WS Q2 use case.</p>
</li>
<li>
<p>2008-07-10: Updated the syntax to the lastest editor's
draft.</p>
</li>
<li>
<p>2008-11-09: Updated the syntax to the lastest editor's
draft.</p>
</li>
</ul>
</div>
</div>
</div>
</body>
</html>