Recursive nodes in XML Schema

XSLTer · April 13th, 2007, 11:59 AM

I have an XML file which I want to generate a schema for. The file, simplified, looks like this:

Code:

<?xml version="1.0" encoding="utf-8" ?>
<nodes>
  <node>
    <node></node>
    <node>
      <node></node>
    </node>
    <text></text>
  </node>
</nodes>

The <node> elements can hold an infinite number of other <node> elements.

Now I auto generated the schema from VS2005 and get:

Code:

<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="nodes">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="node">
          <xs:complexType>
            <xs:sequence>
              <xs:element maxOccurs="unbounded" name="node">
                <xs:complexType>
                  <xs:sequence minOccurs="0">
                    <xs:element name="node" />
                  </xs:sequence>
                </xs:complexType>
              </xs:element>
              <xs:element name="text" />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

I cannot work out how to modify the schema to tell it about the <node> once and make it understand that <node> can nest other <node>'s.

Any ideas?

mhkay · April 13th, 2007, 12:25 PM

You want something like:

<xs:element name="nodes">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="node" maxOccurs="unbounded"/>
      </xs:sequence>
    </xs:complexType>
</xs:element>

<xs:element name="node">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="node" maxOccurs="unbounded"/>
        <xs:element name="text" type="xs:string"/>
      </xs:sequence>
    </xs:complexType>
</xs:element>

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference