<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="Ratio" />
  <meta>
    <lastUpdated value="2019-11-01T09:29:23.356+11:00" />
  </meta>
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
    <valueCode value="normative" />
  </extension>
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-normative-version">
    <valueCode value="4.0.0" />
  </extension>
  <url value="http://hl7.org/fhir/StructureDefinition/Ratio" />
  <version value="4.0.1" />
  <name value="Ratio" />
  <status value="active" />
  <date value="2019-11-01T09:29:23+11:00" />
  <publisher value="HL7 FHIR Standard" />
  <contact>
    <telecom>
      <system value="url" />
      <value value="http://hl7.org/fhir" />
    </telecom>
  </contact>
  <description value="Base StructureDefinition for Ratio Type: A relationship of two Quantity values - expressed as a numerator and a denominator." />
  <purpose value="Need to able to capture ratios for some measurements (titers) and some rates (costs)." />
  <fhirVersion value="4.0.1" />
  <mapping>
    <identity value="v2" />
    <uri value="http://hl7.org/v2" />
    <name value="HL7 v2 Mapping" />
  </mapping>
  <mapping>
    <identity value="rim" />
    <uri value="http://hl7.org/v3" />
    <name value="RIM Mapping" />
  </mapping>
  <kind value="complex-type" />
  <abstract value="false" />
  <type value="Ratio" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Element" />
  <derivation value="specialization" />
  <snapshot>
    <element id="Ratio">
      <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
        <valueCode value="normative" />
      </extension>
      <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-normative-version">
        <valueCode value="4.0.0" />
      </extension>
      <path value="Ratio" />
      <short value="A ratio of two Quantity values - a numerator and a denominator" />
      <definition value="A relationship of two Quantity values - expressed as a numerator and a denominator." />
      <comment value="The Ratio datatype should only be used to express a relationship of two numbers if the relationship cannot be suitably expressed using a Quantity and a common unit.  Where the denominator value is known to be fixed to &quot;1&quot;, Quantity should be used instead of Ratio." />
      <min value="0" />
      <max value="*" />
      <base>
        <path value="Ratio" />
        <min value="0" />
        <max value="*" />
      </base>
      <condition value="ele-1" />
      <constraint>
        <key value="ele-1" />
        <severity value="error" />
        <human value="All FHIR elements must have a @value or children" />
        <expression value="hasValue() or (children().count() &gt; id.count())" />
        <xpath value="@value|f:*|h:div" />
        <source value="http://hl7.org/fhir/StructureDefinition/Element" />
      </constraint>
      <constraint>
        <key value="rat-1" />
        <severity value="error" />
        <human value="Numerator and denominator SHALL both be present, or both are absent. If both are absent, there SHALL be some extension present" />
        <expression value="(numerator.empty() xor denominator.exists()) and (numerator.exists() or extension.exists())" />
        <xpath value="(count(f:numerator) = count(f:denominator)) and ((count(f:numerator) &gt; 0) or (count(f:extension) &gt; 0))" />
      </constraint>
      <isModifier value="false" />
      <mapping>
        <identity value="rim" />
        <map value="n/a" />
      </mapping>
      <mapping>
        <identity value="v2" />
        <map value="N/A" />
      </mapping>
      <mapping>
        <identity value="rim" />
        <map value="RTO" />
      </mapping>
    </element>
    <element id="Ratio.id">
      <path value="Ratio.id" />
      <representation value="xmlAttr" />
      <short value="Unique id for inter-element referencing" />
      <definition value="Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces." />
      <min value="0" />
      <max value="1" />
      <base>
        <path value="Element.id" />
        <min value="0" />
        <max value="1" />
      </base>
      <type>
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="string" />
        </extension>
        <code value="http://hl7.org/fhirpath/System.String" />
      </type>
      <isModifier value="false" />
      <isSummary value="false" />
      <mapping>
        <identity value="rim" />
        <map value="n/a" />
      </mapping>
    </element>
    <element id="Ratio.extension">
      <path value="Ratio.extension" />
      <slicing>
        <discriminator>
          <type value="value" />
          <path value="url" />
        </discriminator>
        <description value="Extensions are always sliced by (at least) url" />
        <rules value="open" />
      </slicing>
      <short value="Additional content defined by implementations" />
      <definition value="May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension." />
      <comment value="There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone." />
      <alias value="extensions" />
      <alias value="user content" />
      <min value="0" />
      <max value="*" />
      <base>
        <path value="Element.extension" />
        <min value="0" />
        <max value="*" />
      </base>
      <type>
        <code value="Extension" />
      </type>
      <constraint>
        <key value="ele-1" />
        <severity value="error" />
        <human value="All FHIR elements must have a @value or children" />
        <expression value="hasValue() or (children().count() &gt; id.count())" />
        <xpath value="@value|f:*|h:div" />
        <source value="http://hl7.org/fhir/StructureDefinition/Element" />
      </constraint>
      <constraint>
        <key value="ext-1" />
        <severity value="error" />
        <human value="Must have either extensions or value[x], not both" />
        <expression value="extension.exists() != value.exists()" />
        <xpath value="exists(f:extension)!=exists(f:*[starts-with(local-name(.), &quot;value&quot;)])" />
        <source value="http://hl7.org/fhir/StructureDefinition/Extension" />
      </constraint>
      <isModifier value="false" />
      <isSummary value="false" />
      <mapping>
        <identity value="rim" />
        <map value="n/a" />
      </mapping>
    </element>
    <element id="Ratio.numerator">
      <path value="Ratio.numerator" />
      <short value="Numerator value" />
      <definition value="The value of the numerator." />
      <min value="0" />
      <max value="1" />
      <base>
        <path value="Ratio.numerator" />
        <min value="0" />
        <max value="1" />
      </base>
      <type>
        <code value="Quantity" />
      </type>
      <constraint>
        <key value="ele-1" />
        <severity value="error" />
        <human value="All FHIR elements must have a @value or children" />
        <expression value="hasValue() or (children().count() &gt; id.count())" />
        <xpath value="@value|f:*|h:div" />
        <source value="http://hl7.org/fhir/StructureDefinition/Element" />
      </constraint>
      <isModifier value="false" />
      <isSummary value="true" />
      <mapping>
        <identity value="rim" />
        <map value=".numerator" />
      </mapping>
    </element>
    <element id="Ratio.denominator">
      <path value="Ratio.denominator" />
      <short value="Denominator value" />
      <definition value="The value of the denominator." />
      <min value="0" />
      <max value="1" />
      <base>
        <path value="Ratio.denominator" />
        <min value="0" />
        <max value="1" />
      </base>
      <type>
        <code value="Quantity" />
      </type>
      <constraint>
        <key value="ele-1" />
        <severity value="error" />
        <human value="All FHIR elements must have a @value or children" />
        <expression value="hasValue() or (children().count() &gt; id.count())" />
        <xpath value="@value|f:*|h:div" />
        <source value="http://hl7.org/fhir/StructureDefinition/Element" />
      </constraint>
      <isModifier value="false" />
      <isSummary value="true" />
      <mapping>
        <identity value="rim" />
        <map value=".denominator" />
      </mapping>
    </element>
  </snapshot>
  <differential>
    <element id="Ratio">
      <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
        <valueCode value="normative" />
      </extension>
      <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-normative-version">
        <valueCode value="4.0.0" />
      </extension>
      <path value="Ratio" />
      <short value="A ratio of two Quantity values - a numerator and a denominator" />
      <definition value="A relationship of two Quantity values - expressed as a numerator and a denominator." />
      <comment value="The Ratio datatype should only be used to express a relationship of two numbers if the relationship cannot be suitably expressed using a Quantity and a common unit.  Where the denominator value is known to be fixed to &quot;1&quot;, Quantity should be used instead of Ratio." />
      <min value="0" />
      <max value="*" />
      <constraint>
        <key value="rat-1" />
        <severity value="error" />
        <human value="Numerator and denominator SHALL both be present, or both are absent. If both are absent, there SHALL be some extension present" />
        <expression value="(numerator.empty() xor denominator.exists()) and (numerator.exists() or extension.exists())" />
        <xpath value="(count(f:numerator) = count(f:denominator)) and ((count(f:numerator) &gt; 0) or (count(f:extension) &gt; 0))" />
      </constraint>
      <mapping>
        <identity value="v2" />
        <map value="N/A" />
      </mapping>
      <mapping>
        <identity value="rim" />
        <map value="RTO" />
      </mapping>
    </element>
    <element id="Ratio.numerator">
      <path value="Ratio.numerator" />
      <short value="Numerator value" />
      <definition value="The value of the numerator." />
      <min value="0" />
      <max value="1" />
      <type>
        <code value="Quantity" />
      </type>
      <isSummary value="true" />
      <mapping>
        <identity value="rim" />
        <map value=".numerator" />
      </mapping>
    </element>
    <element id="Ratio.denominator">
      <path value="Ratio.denominator" />
      <short value="Denominator value" />
      <definition value="The value of the denominator." />
      <min value="0" />
      <max value="1" />
      <type>
        <code value="Quantity" />
      </type>
      <isSummary value="true" />
      <mapping>
        <identity value="rim" />
        <map value=".denominator" />
      </mapping>
    </element>
  </differential>
</StructureDefinition>