<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified"
  xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="attribute">
    <xs:complexType>
      <xs:simpleContent>
        <xs:extension base="xs:string">
          <xs:attribute type="xs:string" name="name" use="required"/>
          <xs:attribute name="type" use="optional">
            <xs:simpleType>
              <xs:restriction base="xs:string">
                <xs:enumeration value="string"/>
                <xs:enumeration value="time"/>
                <xs:enumeration value="integer"/>
                <xs:enumeration value="float"/>
                <xs:enumeration value="boolean"/>
              </xs:restriction>
            </xs:simpleType>
          </xs:attribute>
          <xs:attribute type="xs:dateTime" name="time" use="optional"/>
        </xs:extension>
      </xs:simpleContent>
    </xs:complexType>
  </xs:element>
  <xs:element name="attributes">
    <xs:complexType mixed="true">
      <xs:sequence>
        <xs:element ref="attribute" maxOccurs="unbounded" minOccurs="0"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="object-type">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="attributes"/>
      </xs:sequence>
      <xs:attribute type="xs:string" name="name" use="required"/>
    </xs:complexType>
    <xs:key name="objectTypeAttributeKey">
      <xs:selector xpath="attributes/attribute"/>
      <xs:field xpath="@name"/>
    </xs:key>
  </xs:element>
  <xs:element name="event-type">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="attributes"/>
      </xs:sequence>
      <xs:attribute type="xs:string" name="name" use="required"/>
    </xs:complexType>
    <xs:key name="eventTypeAttributeKey">
      <xs:selector xpath="attributes/attribute"/>
      <xs:field xpath="@name"/>
    </xs:key>
  </xs:element>
  <xs:element name="object">
    <xs:complexType mixed="true">
      <xs:sequence>
        <xs:element ref="attributes" minOccurs="0"/>
        <xs:element ref="objects" minOccurs="0"/>
      </xs:sequence>
      <xs:attribute type="xs:string" name="object-id" use="optional"/>
      <xs:attribute type="xs:string" name="qualifier" use="optional"/>
      <xs:attribute type="xs:string" name="id" use="optional"/>
      <xs:attribute type="xs:string" name="type" use="required"/>
    </xs:complexType>
  </xs:element>
  <xs:element name="objects">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="object" maxOccurs="unbounded" minOccurs="0"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="event">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="attributes"/>
        <xs:element ref="objects"/>
      </xs:sequence>
      <xs:attribute type="xs:string" name="id" use="required"/>
      <xs:attribute type="xs:string" name="type" use="required"/>
      <xs:attribute type="xs:dateTime" name="time" use="required"/>
    </xs:complexType>
  </xs:element>
  <xs:element name="object-types">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="object-type" maxOccurs="unbounded" minOccurs="0"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="event-types">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="event-type" maxOccurs="unbounded" minOccurs="0"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="events">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="event" maxOccurs="unbounded" minOccurs="0"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="log">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="object-types"/>
        <xs:element ref="event-types"/>
        <xs:element ref="objects"/>
        <xs:element ref="events"/>
      </xs:sequence>
    </xs:complexType>
    <xs:key name="objectTypeKey">
      <xs:selector xpath="object-types/object-type"/>
      <xs:field xpath="@name"/>
    </xs:key>
    <xs:key name="objectKey">
      <xs:selector xpath="objects/object"/>
      <xs:field xpath="@id"/>
    </xs:key>
    <xs:key name="eventTypeKey">
      <xs:selector xpath="event-types/event-type"/>
      <xs:field xpath="@name"/>
    </xs:key>
    <xs:key name="eventKey">
      <xs:selector xpath="events/event"/>
      <xs:field xpath="@id"/>
    </xs:key>
    <xs:keyref name="objectTypeRef" refer="objectTypeKey">
      <xs:selector xpath="objects/object"/>
      <xs:field xpath="@type"/>
    </xs:keyref>
    <xs:keyref name="eventTypeRef" refer="eventTypeKey">
      <xs:selector xpath="events/event"/>
      <xs:field xpath="@type"/>
    </xs:keyref>
    <xs:keyref name="objectObjectRef" refer="objectKey">
      <xs:selector xpath="objects/object/objects/object"/>
      <xs:field xpath="@object-id"/>
    </xs:keyref>
    <xs:keyref name="eventObjectRef" refer="objectKey">
      <xs:selector xpath="events/event/objects/object"/>
      <xs:field xpath="@object-id"/>
    </xs:keyref>
    <xs:keyref name="objectAttributeRef" refer="objectTypeAttributeKey">
      <xs:selector xpath="objects/object/attributes/attribute"/>
      <xs:field xpath="@name"/>
    </xs:keyref>
    <xs:keyref name="eventAttributeRef" refer="eventTypeAttributeKey">
      <xs:selector xpath="events/event/attributes/attribute"/>
      <xs:field xpath="@name"/>
    </xs:keyref>
  </xs:element>
</xs:schema>