<StructureDefinition xmlns="http://hl7.org/fhir">
  <url value="https://example.org/fhir/StructureDefinition/MirjamsDecemberObservation" />
  <name value="MirjamsDecemberObservation" />
  <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="mir-obs-1" />
        <severity value="error" />
        <human value="You have to fill in the value or the note field" />
        <expression value="value.exists() or note.exists()" />
      </constraint>
    </element>
    <element id="Observation.code">
      <path value="Observation.code" />
      <patternCodeableConcept>
        <coding>
          <system value="http://snomed.info/sct" />
          <code value="38764237687265" />
        </coding>
      </patternCodeableConcept>
      <mustSupport value="true" />
    </element>
    <element id="Observation.subject">
      <path value="Observation.subject" />
      <min value="1" />
      <type>
        <code value="Reference" />
        <targetProfile value="https://example.org/fhir/StructureDefinition/MirjamsDecemberPatient" />
      </type>
      <mustSupport value="true" />
    </element>
    <element id="Observation.value[x]">
      <path value="Observation.value[x]" />
      <condition value="mir-obs-1" />
    </element>
    <element id="Observation.note">
      <path value="Observation.note" />
      <condition value="mir-obs-1" />
    </element>
  </differential>
</StructureDefinition>