<StructureDefinition xmlns="http://hl7.org/fhir">
  <url value="https://example.org/fhir/StructureDefinition/MirjamsObservation" />
  <name value="MirjamsObservation" />
  <status value="draft" />
  <fhirVersion value="4.0.1" />
  <kind value="resource" />
  <abstract value="false" />
  <type value="Observation" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Observation" />
  <derivation value="constraint" />
  <differential>
    <element id="Observation">
      <path value="Observation" />
      <constraint>
        <key value="mirjam-1" />
        <severity value="error" />
        <human value="Fill in the value field, or use the note field" />
        <expression value="value.exists() or note.exists()" />
      </constraint>
    </element>
    <element id="Observation.subject">
      <path value="Observation.subject" />
      <type>
        <code value="Reference" />
        <targetProfile value="http://mirjams.examples.org/StructureDefinition/mirjams-course-patient-2" />
      </type>
    </element>
    <element id="Observation.value[x]">
      <path value="Observation.value[x]" />
      <condition value="mirjam-1" />
    </element>
    <element id="Observation.note">
      <path value="Observation.note" />
      <condition value="mirjam-1" />
    </element>
  </differential>
</StructureDefinition>