<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">

   <xs:element name="notebook">
      <xs:complexType>
         <xs:sequence maxOccurs="unbounded">
            <xs:element name="note" type="Note"/>
         </xs:sequence>
         <xs:attribute ref="date"/>
      </xs:complexType>
   </xs:element>

   <xs:complexType name="Note">
      <xs:sequence>
         <xs:element name="subject" type="xs:string"/>
         <xs:element name="body" type="xs:string"/>
      </xs:sequence>

      <xs:attribute ref="date" use="required"/>
      <xs:attribute name="category" type="xs:string"/>

   </xs:complexType>

   <xs:attribute name="date" type="xs:date"/>
</xs:schema>