• Chapter 1: Getting Started with Stylus Studio®
• Chapter 2: Editing and Querying XML
• Chapter 3: Converting Non-XML Files to XML
• Chapter 4: Working with XSLT
• Chapter 5: Creating XSLT Using the XSLT Mapper
• Chapter 6: Debugging Stylesheets
• Chapter 7: Defining XML Schemas
• Chapter 8: Defining Document Type Definitions
• Chapter 9: Writing XPath Expressions
• Chapter 10: Working with XQuery in Stylus Studio
• Chapter 11: Composing Web Service Calls
• Chapter 12: Accessing Relational Data as XML
• Chapter 13: Building XML Pipelines
  • What is an XML Pipeline?
  • The XML Pipeline Editor
  • Steps for Building an XML Pipeline
  • Planning an XML Pipeline
  • Use Case: Building order.pipeline
    • order.pipeline Requirements
    • Getting Started: Creating a New XML Pipeline
    • XML Pipeline Scenarios
    • Specifying an Execution Framework
    • Configuring Data Sources
    • Using XQuery to Merge Source File Data
      • Using Variables to Reference Data Sources
      • Looking at the XQuery Code
    • Adding an XQuery Node
    • Setting the XQuery Node Data Sources
    • Testing the XML Pipeline
    • Setting a Value for an Output Port
    • Designing a Report from the XML Document
    • Adding XSLT and XQuery Transformations
    • Finishing Up
  • Working with Nodes
  • Working with the XML Pipeline Diagram
  • Debugging an XML Pipeline
  • Generating Code for an XML Pipeline
  • XML Pipeline Node Properties Reference
• Chapter 14: Publishing XML Data
• Chapter 15: Integrating with Third-Party File Systems
• Chapter 16: Extending Stylus Studio
• Chapter 17: The Stylus Studio Java API
• Chapter 18: Stylus Studio GUI Reference

Home > Online Product Documentation > Table of Contents > Using XQuery to Merge Source File Data

Using XQuery to Merge Source File Data

As described in <xHyperlink>order.pipeline Requirements, the data required for our report comes from two files - a text file, booksXML.txt, and an EDI file, order.edi. Both files have the book's ISBN, and we will use that number to select matching data. This will provide us with the following information required by our report:

To join data from these different documents we will use an XQuery document created using the XQuery Mapper. Once we have defined that XQuery document, we can add the XQuery node to our XML pipeline.

Using Variables to Reference Data Sources

Because we want our XQuery to be easy to parameterize, we will create it using external variables to reference our two data sources, booksXML.txt and order.edi. Once the data sources for the XQuery are defined, we can use the XQuery Mapper to map desired nodes from these source documents to nodes in the XML Schema that represents the structure to which the resulting XML must conform.

If you open createFullOrder.xquery, which is in the pipelines\order folder of the examples project where you installed Stylus Studio, you can see how this was done. As shown in Figure 401, createFullOrder.xquery uses variable declarations, $ediOrder and $allBooks, for the non-XML data sources. Stylus Studio adapters convert these data sources to XML on-the-fly, any time the XQuery (or an XML pipeline that uses the XQuery) is executed. Thus, if the data in either booksXML.txt and order.edi changes, the report resulting from the XML pipeline will change, too.

Figure 401. Variables Created for Non-XML Data Sources

To use non-XML as a source document for XQuery Mapper:

To specify a non-XML data source as an XML source for the XQuery Mapper, you

This displays the Open dialog box.

Figure 402. Using Non-XML Data as an XQuery Data Source

Next, we need to create global variables for the two source documents. This way, the XQuery code that Stylus Studio generates will use variable declarations instead of document functions to reference our data sources.

To associate the source schema with a global variable:

Stylus Studio displays the Associate Schema with Variable dialog box.

Figure 403. Associate Schema with Variable Dialog Box

When a variable is created ( allBooks, for example), Stylus Studio creates a declaration like the following in the XQuery source code:

declare variable $allBooks as document-node() external;
               

            

Looking at the XQuery Code

Before moving on with the XML pipeline creation, let's a quick look at the XQuery code in createFullOrder.xquery:

declare variable $ediOrder as document-node() external;
               
declare variable $allBooks as document-node() external;
               
 
               
<root>
               
	{
               
	for $GROUP_28 in $ediOrder/EDIFACT/ORDERS/GROUP_28,
               
	    $row in $allBooks/table/row
               
	where $GROUP_28/LIN/LIN03/LIN0301/text() = $row/isbn/text()
               
	return
               
	<book>
               
		<title>
               
			{$row/title/text()}
               
		</title>
               
		<quantity>
               
			{$GROUP_28/QTY/QTY01/QTY0102/text()}
               
		</quantity>
               
		<ISBN>
               
			{$GROUP_28/LIN/LIN03/LIN0301/text()}
               
		</ISBN>
               
	</book>
               
	}
               
</root>
               

            

The first two lines contain the variable declarations for booksXML.txt and order.edi, our two source files. A FLWOR block (For, Let, Where, Order by, Return) matches ISBN numbers from order.edi with those in books.xml, and when it finds a match, it returns

All of this code was created automatically as a result of mapping nodes from our source documents to nodes in an XML Schema, fullOrder.xsd, which was provided by the organization in our enterprise that requested the inventory report - all XML resulting from the createFullOrder.xquery must conform to this XML Schema.

Figure 404. XQuery Mapper Used to Generate createFullOrder.xquery

See Building an XQuery Using the Mapper for more information on using the XQuery Mapper.