c# validate XML with XSD on unknown nested elements

Question

Is it possible to create a XSD for validating a (unknown) nested structure? I recently changed my XML data to be hierarchical

<root>
    <record Object_Number="1" Object_Level="1" Object_Heading="Introduction" Object_Text="" Milestones="" Unique_ID="" Field_type="Info" SG_attribute="" Object_Identifier="1" Object_URL="doors://D1DDBAPP04:36677/?version=2&amp;prodID=0&amp;view=0000001a&amp;urn=urn:telelogic::1-432aa0956f684cff-O-1-00028f60">
        <record Object_Number="1.1" Object_Level="2" Object_Heading="What is " Object_Text="" Milestones="" Unique_ID="" Field_type="Info" SG_attribute="" Object_Identifier="23" Object_URL="doors://D1DDBAPP04:36677/?version=2&amp;prodID=0&amp;view=0000001a&amp;urn=urn:telelogic::1-432aa0956f684cff-O-23-00028f60">
            <record Object_Number="1.1.0-1" Object_Level="3" Object_Heading="" Object_Text="This document is, in fact, a database that summarizes specification and different aspects of diagnostic functions implemented in the system." Milestones="" Unique_ID="" Field_type="Info" SG_attribute="" Object_Identifier="24" Object_URL="doors://D1DDBAPP04:36677/?version=2&amp;prodID=0&amp;view=0000001a&amp;urn=urn:telelogic::1-432aa0956f684cff-O-24-00028f60"></record></record>
        <record Object_Number="1.2" Object_Level="2" Object_Heading="Review Checklist" 

This is because original data is hierarchical and makes more sense to exploit XML nested capability rather than plain records.

So now I have nested

The only known thing is that each record have precise attributes and I want to check and spot error if one of them have incorrect (inconsistent) attribute list and/or incorrect values.

For old (plain records, not nested) I use this for validating

xdoc = XDocument.Load(myXml);
                   string xsdMarkup = @"
<xs:schema attributeFormDefault='unqualified' elementFormDefault='qualified' xmlns:xs='http://www.w3.org/2001/XMLSchema'>
  <xs:element name='root'>
    <xs:complexType>
      <xs:sequence>
        <xs:element minOccurs='1' maxOccurs='unbounded' name='record'>
          <xs:complexType>
            <xs:sequence>
              <xs:element minOccurs='1' maxOccurs='1' name='Object_Number' type='xs:string' />
              <xs:element minOccurs='1' maxOccurs='1' name='Object_Level' type='xs:unsignedByte' />
              <xs:element minOccurs='1' maxOccurs='1' name='Object_Heading' type='xs:string' />
              <xs:element minOccurs='1' maxOccurs='1' name='Object_Text' type='xs:string' />
              <xs:element minOccurs='1' maxOccurs='1' name='Milestones' type='xs:string' />
              <xs:element minOccurs='1' maxOccurs='1' name='Unique_ID' type='xs:string' />
              <xs:element minOccurs='1' maxOccurs='1' name='Field_type' type='xs:string' />
              <xs:element minOccurs='1' maxOccurs='1' name='SG_attribute' type='xs:string' />
              <xs:element minOccurs='1' maxOccurs='1' name='Object_Identifier' type='xs:unsignedShort' />
              <xs:element minOccurs='1' maxOccurs='1' name='Object_URL' type='xs:string' />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>
";
                    XmlSchemaSet schemas = new XmlSchemaSet();
                    schemas.Add("", XmlReader.Create(new StringReader(xsdMarkup)));

                    string msg = "";
                    xdoc.Validate(schemas, (o, err) =>
                    {
                        msg += err.Message;
                        //Console.WriteLine("{0}", err.Message);
                        //errors = true;
                    });

                    if (msg == "")
                        e.Result = true;

The XSD schema I generated with Visual Studio.

Now, for hierarchical data, generated XSD seems to follow the deep structure which is fine for know level deeps, but will fail for another one deep

<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="root">
    <xs:complexType>
      <xs:sequence>
        <xs:element maxOccurs="unbounded" name="record">
          <xs:complexType>
            <xs:sequence minOccurs="0">
              <xs:element maxOccurs="unbounded" name="record">
                <xs:complexType>
                  <xs:sequence minOccurs="0">
                    <xs:element maxOccurs="unbounded" name="record">
                      <xs:complexType>
                        <xs:sequence minOccurs="0">
                          <xs:element maxOccurs="unbounded" name="record">
                            <xs:complexType>
                              <xs:attribute name="Object_Number" type="xs:string" use="required" />
                              <xs:attribute name="Object_Level" type="xs:unsignedByte" use="required" />
                              <xs:attribute name="Object_Heading" type="xs:string" use="required" />
                              <xs:attribute name="Object_Text" type="xs:string" use="required" />
                              <xs:attribute name="Milestones" type="xs:string" use="required" />
                              <xs:attribute name="Unique_ID" type="xs:string" use="required" />
                              <xs:attribute name="Field_type" type="xs:string" use="required" />
                              <xs:attribute name="SG_attribute" type="xs:string" use="required" />
                              <xs:attribute name="Object_Identifier" type="xs:unsignedShort" use="required" />
                              <xs:attribute name="Object_URL" type="xs:string" use="required" />
                            </xs:complexType>
...
...
...

So it is possible to check a nested scheme with XSD?

Thanks very much for hints,

Answer 1

Define the structure recursively as

<xs:element name="record">
  <xs:complexType>
    <xs:sequence minOccurs="0" maxOccurs="unbounded">
      <xs:element ref="record"/>
      ....