Version 1.1, 12th January 2004

Introduction

In order to ensure that the contents of the recordData field of a record are well formed XML in their own right, the result of evaluating an XPath expression needs to be encoded in an XML form. A simple schema has been defined which can encapsulate these objects in an easy to process fashion.

The unique identifier for the XPath result schema is: info:srw/schema/1/xpath-1.0

Elements

The examples below will help to illustrate the usage of the schema, but a quick rundown of the various elements is called for first.

• The top level element is 'result'. It must contain only one of the 'nodeSet', 'string', 'number' or 'boolean' elements.
• The 'string', 'number' and 'boolean' elements contain character data. Boolean values should be represented as 'true' or 'false', case insensitive.
• The 'nodeSet' element may contain zero or more 'node's to represent the matched nodes within the XML tree. It also has a 'schema' attribute which may contain the unique identifier of the schema that the results are drawn from.
• The 'node' element may contain any data, including further XML elements. It has two attributes, both of which are optional. The 'type' attribute should contain one of 'element', 'attribute', 'text', 'comment', or 'processing' based on the type of node within. The 'path' attribute may contain the full XPath to the node within the document.
• Matched nodes should be included directly within the node tag as they would appear in the document. Attribute nodes require special processing -- the name of the element should be 'attr' and the name of the matched attribute should be put into a 'name' attribute on the element. The value of the attribute should be included as the contents of the element.

Examples

The following are hopefully informative examples of the use of the schema.

<result> <nodeSet schema="info:srw/schema/1/dc-v1.1> <node type="element" path="/dc/title"> <title>This is a title element</title> </node> <node type="attribute"> <attr name="id">attr1-1</attr> </node> <node type="text"> This is a text node. </node> <node type="comment"> <!-- Comment --> </node> <node type="processing"> <?foo type="bar"?> </node> </nodeSet> </result> <result> <string>This is a string result</string> </result> <result> <number>1</number> </result> <result> <boolean>true</boolean> </result>