XML Features of Oracle 8i and 9i (4/7) - exploring XML

XML Features of Oracle 8i and 9i

XSQL servlet

XSQL servlet - as distinct from the XSU described above - is a tool that processes SQL queries and outputs the result set as XML. As a standard java servlet it should work with any java enabled web server. As input it uses an "XSQL" file: an XML file containing embedded SQL queries. XSQL pages are similar to ASPs/JSPs but give XML as output and allow for standard XML processing using XSL.

Example XSQL file:

<?xml version="1.0"?>
<xsql:query connection="demo" xmlns:xsql="urn:oracle-xsql">
  SELECT Carrier, FlightNumber, Origin, ExpectedTime
  FROM FlightSchedule
  WHERE Destination = '{@City}'
</xsql:query>

Called via:

https://mywebserver/flights.xsql?City=LHR

Would result in this output:

<?xml version="1.0"?>
<ROWSET>
  <ROW num="1">
    <CARRIER>LH</CARRIER>
    <FLIGHTNUMBER>LH343</FLIGHTNUMBER>
    <ORIGIN>London</ORIGIN>
    <DUE>12:44</DUE>
  </ROW>
  <ROW num="2">
    <CARRIER>BA</CARRIER>
    <FLIGHTNUMBER>BA272</FLIGHTNUMBER>
    <ORIGIN>Birmingham</ORIGIN>
    <DUE>02:05</DUE>
  </ROW>
</ROWSET>

But XSQL pages can also contain references to stylesheets such as:

<?xml-stylesheet type="text/xsl" href="flight-list.xsl"?>

to convert the above into HTML or other formats.

Other features of XSQL pages:

• Insert and updates also possible
• Can contain more than one query
• Queries can be parameterised i.e WHERE Destination = '{@City}'
• Variables for pagination of a recordset available e.g

XSQL servlet can be called in different ways:

• via an http request e.g https://myserver/myquery.xsql (when enabled as a servlet)
• via a command line utility e.g xsql airport.xsql airport=LHR xml-stylesheet=none
• from a java or jsp or other XSQL file

Next is the XML class generator...

Produced by Michael Claßen

URL: https://www.webreference.com/xml/column81/4.html
Created: May 10, 2003
Revised: May 10, 2003