<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           xmlns:vc="http://www.w3.org/2007/XMLSchema-versioning" vc:minVersion="1.1">

  <xs:element name="root">
    <xs:complexType>
      <xs:sequence>
        <xs:element minOccurs="0" maxOccurs="1" name="Type" type="xs:integer" />
        <xs:element minOccurs="0" maxOccurs="1" name="Comment" type="xs:string" />
      </xs:sequence>
      
      <xs:assert test="Comment or not(Type = 0)"/>
    </xs:complexType>
  </xs:element>

</xs:schema>