Example: Using XSLT for data exchange

An example that illustrates how to use the built-in XSLTRANSFORM function to convert XML documents for data exchange.

This example illustrates how to use XSLT for data exchange by using parameters with the stylesheet to produce different data exchange formats at runtime.

We use a stylesheet that incorporates xsl:param elements to capture data from a parameter file.

INSERT INTO Display_productdetails values(1, '<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
                   xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:param name="headline"/>
<xsl:param name="supermarketname"/>
<xsl:template match="product">
   <html>
             <head/>
                <body>
                <h1><xsl:value-of select="$headline"/></h1>
                <table border="1">
                        <th>
                        <tr>
                         <td width="80">product ID</td>
                         <td width="200">product name</td>
                         <td width="200">price</td>
                         <td width="50">details</td>
                         <xsl:choose>
   <xsl:when test="$supermarket =''true'' ">
                                 <td width="200">BIG BAZAAR super market</td>
                                </xsl:when>
    </xsl:choose>
                         </tr>
                        </th>
                        <xsl:apply-templates/>
                </table>
                </body>
                </html>
        </xsl:template>
      <xsl:template match="product">
             <tr>
                   <td><xsl:value-of select="@pid"/></td>
                   <td><xsl:value-of select="/product/description/name"/></td>
                   <td><xsl:value-of select="/product/description/price"/></td>
                   <td><xsl:value-of select="/product/description/details"/></td>
                  </tr>
     </xsl:template>
  </xsl:stylesheet>'
);

The parameter file contains parameters corresponding to the ones in the XSLT template, with content:

CREATE TABLE PARAM_TAB (DOCID INTEGER, PARAM VARCHAR (10K));

INSERT INTO PARAM_TAB VALUES
(1,
'<?xml version="1.0"?>
<params xmlns="http://www.ibm.com/XSLTransformParameters">
        <param name="supermarketname" value="true"/>
        <param name="headline">BIG BAZAAR super market</param>
</params>'
);

You can then apply the parameter file at runtime using the following command:

SELECT XSLTRANSFORM (XML_DOC USING XSL_DOC WITH PARAM AS CLOB (1M)) 
   FROM product_details X, PARM_TAB P WHERE X.DOCID=P.DOCID;

The result is HTML, but with content determined by the parameter file and tests done against the content of the XML document:

<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<h1></h1>
<table border="1">
<th>
<tr>
<td width="80">product ID</td>
<td width="200">product Name</td>
<td width="200">price</td>
<td width="50">Details</td>
</tr>
</th> 
</table>
</body>
</html>

In other applications, the output of XSLTRANSFORM might not be HTML but rather another XML document or a file using a different data format, such as an EDI file.

For data exchange applications, the parameter file could contain EDI or SOAP file header information such as e-mail or port addresses, or other critical data unique to a particular transaction. Since the XML used in the previous examples is an inventory record, it is easy to imagine using XSLT to repackage this record for exchange with a client's purchasing system.