Release 5 Ballot

This page is part of the FHIR Specification (v5.0.0-ballot: R5 Ballot - see ballot notes). The current version which supercedes this version is 5.0.0. For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B R4 R3 R2

Example StructureDefinition/Extension (XML)

Modeling and Methodology Work GroupMaturity Level: N/AStandards Status: Informative

Raw XML (canonical form + also see XML Format Specification)

StructureDefinition for Extension

<?xml version="1.0" encoding="UTF-8"?>

<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="Extension"/> 
  <text> 
    <status value="generated"/> 
    <div xmlns="http://www.w3.org/1999/xhtml">
      <table border="0" cellpadding="0" cellspacing="0" style="border: 0px #F0F0F0 solid; font-size: 11px; font-family: verdana; vertical-align:
       top;">
        <tr style="border: 1px #F0F0F0 solid; font-size: 11px; font-family: verdana; vertical-align:
         top">
          <th class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">
            <a href="formats.html#table" title="The logical name of the element">Name</a> 
          </th> 
          <th class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">
            <a href="formats.html#table" title="Information about the use of the element">Flags</a> 
          </th> 
          <th class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">
            <a href="formats.html#table" title="Minimum and Maximum # of times the the element can appear in the instance">Card.</a> 
          </th> 
          <th class="hierarchy" style="width: 100px">
            <a href="formats.html#table" title="Reference to the type of the element">Type</a> 
          </th> 
          <th class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">
            <a href="formats.html#table" title="Additional information about the element">Description &amp; Constraints</a> 
            <span style="float: right">
              <a href="formats.html#table" title="Legend for this format">
                <img alt="doco" src="help16.png" style="background-color: inherit"/> 
              </a> 
            </span> 
          </th> 
        </tr> 
        <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color:
         white">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;bas
          e64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAI0lEQVR42u3QIQEAAAACIL/6/4MvTAQOkLYBAAB4kA
          AAANwMad9AqkRjgNAAAAAASUVORK5CYII=)">
            <img alt="." class="hierarchy" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpw
            YAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI1
            2P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:image/png;base64,R0lGODlhEAAQAPQfAOvGUf7ztuvPMf/78/fkl/Pbg+u8Rvjqteu2Pf3zxPz36Pz0z+vTmPz
            urPvuw/npofbjquvNefHVduuyN+uuMu3Oafbgjfnqvf/3zv/3xevPi+vRjP/20/bmsP///wD/ACH5BAEKAB8ALAAAAAAQA
            BAAAAVl4CeOZGme5qCqqDg8jyVJaz1876DsmAQAgqDgltspMEhMJoMZ4iy6I1AooFCIv+wKybziALVAoAEjYLwDgGIpJhM
            slgxaLR4/3rMAWoBp32V5exg8Shl1ckRUQVaMVkQ2kCstKCEAOw==" style="background-color: white; background-color: inherit" title="Element"/>  
            <a href="extensibility-definitions.html#Extension" title="Extension : Optional Extension Element - found in all resources.">Extension</a> 
          </td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">
            <a href="versions.html#std-process" style="padding-left: 3px; padding-right: 3px; border: 1px grey solid; font-weight: bold;
             color: black; background-color: #e6ffe6" title="Standards Status = Normative">N</a> 
          </td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px"/> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">
            <a href="types.html#Element">Element</a> 
          </td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">Optional Extensions Element
            <br/>  
            <span style="font-style: italic" title="ext-1">+ Rule: Must have either extensions or value[x], not both</span> 
            <br/>  
            <br/>  Elements defined in Ancestors: 
            <a href="types.html#Element" title="Unique id for the element within a resource (for internal references). This may
             be any string value that does not contain spaces.">id</a> , 
            <a href="types.html#Element" title="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.">extension</a> 
          </td> 
        </tr> 

        <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color:
         #F7F7F7">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image:
           url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAL0lEQVR42u3XsQ0AQAg
          CQHdl/xn8jxvYWB3JlTR0VJLa+OltBwAAYP6EEQAAgCsPVYVAgIJrA/sAAAAASUVORK5CYII=)">
            <img alt="." class="hierarchy" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpw
            YAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI1
            2P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpw
            YAAAAB3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y
            +2RsQ0AIAzDav7/2VzQwoCY4iWbZSmo1QGoUgNMghvWaIejPQW/CrrNCylIwcOCDYfLNRcNer4SAAAAAElFTkSuQmCC" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAACXBIWXMAAAsTAAALEwEAmpw
            YAAAARklEQVQ4y2P8//8/AyWAhYFCMAgMuHjx4n+KXaCv+I0szW8WpCG8kFO1lGFKW/SIjAUYgxz/MzAwMDC+nqhDUTQyj
            uYFBgCNmhP4OvTRgwAAAABJRU5ErkJggg==" style="background-color: #F7F7F7; background-color: inherit" title="Primitive Data Type"/>  
            <a href="extensibility-definitions.html#Extension.url" title="Extension.url : Source of the definition for the extension code - a logical name
             or a URL.">url</a> 
          </td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px"/> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px">1..1</td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px">
            <a href="datatypes.html#uri">uri</a> 
          </td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px">identifies the meaning of the extension
            <br/>  
          </td> 
        </tr> 

        <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color:
         white">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;bas
          e64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAI0lEQVR42u3QIQEAAAACIL/6/4MvTAQOkLYBAAB4kA
          AAANwMad9AqkRjgNAAAAAASUVORK5CYII=)">
            <img alt="." class="hierarchy" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpw
            YAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI1
            2P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpw
            YAAAAB3RJTUUH3wYeFzME+lXFigAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y
            +3OsRUAIAjEUOL+O8cJABttJM11/x1qZAGqRBEVcNIqdWj1efDqQbb3HwwwwEfABmQUHSPM9dtDAAAAAElFTkSuQmCC" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:image/png;base64,R0lGODlhEAAQAPZ/APrkusOiYvvfqbiXWaV2G+jGhdq1b8GgYf3v1frw3vTUlsWkZNewbcS
            jY/DQkad4Hb6dXv3u0f3v1ObEgfPTlerJiP3w1v79+e7OkPrfrfnjuNOtZPrpydaxa+/YrvvdpP779ZxvFPvnwKKBQaFyF
            /369M2vdaqHRPz58/HNh/vowufFhfroxO3OkPrluv779tK0e6JzGProwvrow9m4eOnIifPTlPDPkP78+Naxaf3v0/zowfX
            Ri+bFhLWUVv379/rnwPvszv3rye3LiPvnv+3MjPDasKiIS/789/3x2f747eXDg+7Mifvu0tu7f+/QkfDTnPXWmPrjsvrjt
            PbPgrqZW+/QlPz48K2EMv36866OUPvowat8Ivvgq/Pbrvzgq/PguvrgrqN0Gda2evfYm9+7d/rpw9q6e/LSku/Rl/XVl/L
            Slfrkt+zVqe7Wqv3x1/bNffbOf59wFdS6if3u0vrqyP3owPvepfXQivDQkO/PkKh9K7STVf779P///wD/ACH5BAEKAH8AL
            AAAAAAQABAAAAemgH+CgxeFF4OIhBdKGwFChYl/hYwbdkoBPnaQkosbG3d3VEpSUlonUoY1Gzo6QkI8SrGxWBOFG4uySgY
            5ZWR3PFy2hnaWZXC/PHcPwkpJk1ShoHcxhQEXSUmtFy6+0iSFVResrjoTPDzdcoU+F65CduVU6KAhhQa3F8Tx8nchBoYuq
            oTLZoAKFRIhqGwqJAULFx0GYpBQeChRIR4TJm6KJMhQRUSBAAA7" style="background-color: white; background-color: inherit" title="Data Type"/>  
            <a href="extensibility-definitions.html#Extension.value_x_" title="Extension.value[x] : Value of extension - must be one of a constrained set of the
             data types (see [Extensibility](extensibility.html) for a list).">value[x]</a> 
          </td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px"/> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">0..1</td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">
            <a href="datatypes.html#open">*</a> 
          </td> 
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px">Value of extension
            <br/>  
          </td> 
        </tr> 

        <tr> 
          <td class="hierarchy" colspan="5">
            <br/>  
            <a href="formats.html#table" title="Legend for this format">
              <img alt="doco" src="help16.png" style="background-color: inherit"/>  Documentation for this format
            </a> 
          </td> 
        </tr> 
      </table> 
    </div> 
  </text> 
  <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/Extension"/> 
  <version value="5.0.0-ballot"/> 
  <name value="Extension"/> 
  <status value="active"/> 
  <experimental value="false"/> 
  <date value="2022-09-10T04:52:37+10:00"/> 
  <publisher value="HL7 FHIR Standard"/> 
  <contact> 
    <telecom> 
      <system value="url"/> 
      <value value="http://hl7.org/fhir"/> 
    </telecom> 
  </contact> 
  <description value="Extension Type: Optional Extension Element - found in all resources."/> 
  <purpose value="The ability to add extensions in a structured way is what keeps FHIR resources
   simple."/> 
  <fhirVersion value="5.0.0-ballot"/> 
  <mapping> 
    <identity value="rim"/> 
    <uri value="http://hl7.org/v3"/> 
    <name value="RIM Mapping"/> 
  </mapping> 
  <kind value="complex-type"/> 
  <abstract value="false"/> 
  <type value="Extension"/> 
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/DataType"/> 
  <derivation value="specialization"/> 
  <snapshot> 
    <element id="Extension">
      <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="Extension"/> 
      <short value="Optional Extensions Element"/> 
      <definition value="Optional Extension Element - found in all resources."/> 
      <min value="0"/> 
      <max value="*"/> 
      <base> 
        <path value="Extension"/> 
        <min value="0"/> 
        <max value="*"/> 
      </base> 
      <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(.), 'value')])"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Extension"/> 
      </constraint> 
      <isModifier value="false"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value="n/a"/> 
      </mapping> 
      <mapping> 
        <identity value="rim"/> 
        <map value="N/A"/> 
      </mapping> 
    </element> 
    <element id="Extension.id">
      <path value="Extension.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> 
    <!--  Note: special primitive values have a FHIRPath system type. e.g. this is compiler
       magic (j)  -->
      <type> 
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="id"/> 
        </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="Extension.extension">
      <path value="Extension.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="Extension.url">
      <path value="Extension.url"/> 
      <representation value="xmlAttr"/> 
      <short value="identifies the meaning of the extension"/> 
      <definition value="Source of the definition for the extension code - a logical name or a URL."/> 
      <comment value="The definition may point directly to a computable or human-readable definition
       of the extensibility codes, or it may be a logical URI as declared in some other
       specification. The definition SHALL be a URI for the Structure Definition defining
       the extension."/> 
      <min value="1"/> 
      <max value="1"/> 
      <base> 
        <path value="Extension.url"/> 
        <min value="1"/> 
        <max value="1"/> 
      </base> 
    <!--  Note: special primitive values have a FHIRPath system type. e.g. this is compiler
       magic (j)  -->
      <type> 
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="uri"/> 
        </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="Extension.value[x]">
      <path value="Extension.value[x]"/> 
      <short value="Value of extension"/> 
      <definition value="Value of extension - must be one of a constrained set of the data types (see [Extensibility](
      extensibility.html) for a list)."/> 
      <min value="0"/> 
      <max value="1"/> 
      <base> 
        <path value="Extension.value[x]"/> 
        <min value="0"/> 
        <max value="1"/> 
      </base> 
      <type> 
        <code value="base64Binary"/> 
      </type> 
      <type> 
        <code value="boolean"/> 
      </type> 
      <type> 
        <code value="canonical"/> 
      </type> 
      <type> 
        <code value="code"/> 
      </type> 
      <type> 
        <code value="date"/> 
      </type> 
      <type> 
        <code value="dateTime"/> 
      </type> 
      <type> 
        <code value="decimal"/> 
      </type> 
      <type> 
        <code value="id"/> 
      </type> 
      <type> 
        <code value="instant"/> 
      </type> 
      <type> 
        <code value="integer"/> 
      </type> 
      <type> 
        <code value="integer64"/> 
      </type> 
      <type> 
        <code value="markdown"/> 
      </type> 
      <type> 
        <code value="oid"/> 
      </type> 
      <type> 
        <code value="positiveInt"/> 
      </type> 
      <type> 
        <code value="string"/> 
      </type> 
      <type> 
        <code value="time"/> 
      </type> 
      <type> 
        <code value="unsignedInt"/> 
      </type> 
      <type> 
        <code value="uri"/> 
      </type> 
      <type> 
        <code value="url"/> 
      </type> 
      <type> 
        <code value="uuid"/> 
      </type> 
      <type> 
        <code value="Address"/> 
      </type> 
      <type> 
        <code value="Age"/> 
      </type> 
      <type> 
        <code value="Annotation"/> 
      </type> 
      <type> 
        <code value="Attachment"/> 
      </type> 
      <type> 
        <code value="CodeableConcept"/> 
      </type> 
      <type> 
        <code value="CodeableReference"/> 
      </type> 
      <type> 
        <code value="Coding"/> 
      </type> 
      <type> 
        <code value="ContactPoint"/> 
      </type> 
      <type> 
        <code value="Count"/> 
      </type> 
      <type> 
        <code value="Distance"/> 
      </type> 
      <type> 
        <code value="Duration"/> 
      </type> 
      <type> 
        <code value="HumanName"/> 
      </type> 
      <type> 
        <code value="Identifier"/> 
      </type> 
      <type> 
        <code value="Money"/> 
      </type> 
      <type> 
        <code value="Period"/> 
      </type> 
      <type> 
        <code value="Quantity"/> 
      </type> 
      <type> 
        <code value="Range"/> 
      </type> 
      <type> 
        <code value="Ratio"/> 
      </type> 
      <type> 
        <code value="RatioRange"/> 
      </type> 
      <type> 
        <code value="Reference"/> 
      </type> 
      <type> 
        <code value="SampledData"/> 
      </type> 
      <type> 
        <code value="Signature"/> 
      </type> 
      <type> 
        <code value="Timing"/> 
      </type> 
      <type> 
        <code value="ContactDetail"/> 
      </type> 
      <type> 
        <code value="DataRequirement"/> 
      </type> 
      <type> 
        <code value="Expression"/> 
      </type> 
      <type> 
        <code value="ParameterDefinition"/> 
      </type> 
      <type> 
        <code value="RelatedArtifact"/> 
      </type> 
      <type> 
        <code value="TriggerDefinition"/> 
      </type> 
      <type> 
        <code value="UsageContext"/> 
      </type> 
      <type> 
        <code value="Availability"/> 
      </type> 
      <type> 
        <code value="ExtendedContactDetail"/> 
      </type> 
      <type> 
        <code value="Dosage"/> 
      </type> 
      <type> 
        <code value="Meta"/> 
      </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="false"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value="N/A"/> 
      </mapping> 
    </element> 
  </snapshot> 
  <differential> 
    <element id="Extension">
      <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="Extension"/> 
      <short value="Optional Extensions Element"/> 
      <definition value="Optional Extension Element - found in all resources."/> 
      <min value="0"/> 
      <max value="*"/> 
      <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(.), 'value')])"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Extension"/> 
      </constraint> 
      <mapping> 
        <identity value="rim"/> 
        <map value="N/A"/> 
      </mapping> 
    </element> 
    <element id="Extension.url">
      <path value="Extension.url"/> 
      <representation value="xmlAttr"/> 
      <short value="identifies the meaning of the extension"/> 
      <definition value="Source of the definition for the extension code - a logical name or a URL."/> 
      <comment value="The definition may point directly to a computable or human-readable definition
       of the extensibility codes, or it may be a logical URI as declared in some other
       specification. The definition SHALL be a URI for the Structure Definition defining
       the extension."/> 
      <min value="1"/> 
      <max value="1"/> 
    <!--  Note: special primitive values have a FHIRPath system type. e.g. this is compiler
       magic (j)  -->
      <type> 
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="uri"/> 
        </extension> 
        <code value="http://hl7.org/fhirpath/System.String"/> 
      </type> 
      <mapping> 
        <identity value="rim"/> 
        <map value="N/A"/> 
      </mapping> 
    </element> 
    <element id="Extension.value[x]">
      <path value="Extension.value[x]"/> 
      <short value="Value of extension"/> 
      <definition value="Value of extension - must be one of a constrained set of the data types (see [Extensibility](
      extensibility.html) for a list)."/> 
      <min value="0"/> 
      <max value="1"/> 
      <type> 
        <code value="base64Binary"/> 
      </type> 
      <type> 
        <code value="boolean"/> 
      </type> 
      <type> 
        <code value="canonical"/> 
      </type> 
      <type> 
        <code value="code"/> 
      </type> 
      <type> 
        <code value="date"/> 
      </type> 
      <type> 
        <code value="dateTime"/> 
      </type> 
      <type> 
        <code value="decimal"/> 
      </type> 
      <type> 
        <code value="id"/> 
      </type> 
      <type> 
        <code value="instant"/> 
      </type> 
      <type> 
        <code value="integer"/> 
      </type> 
      <type> 
        <code value="integer64"/> 
      </type> 
      <type> 
        <code value="markdown"/> 
      </type> 
      <type> 
        <code value="oid"/> 
      </type> 
      <type> 
        <code value="positiveInt"/> 
      </type> 
      <type> 
        <code value="string"/> 
      </type> 
      <type> 
        <code value="time"/> 
      </type> 
      <type> 
        <code value="unsignedInt"/> 
      </type> 
      <type> 
        <code value="uri"/> 
      </type> 
      <type> 
        <code value="url"/> 
      </type> 
      <type> 
        <code value="uuid"/> 
      </type> 
      <type> 
        <code value="Address"/> 
      </type> 
      <type> 
        <code value="Age"/> 
      </type> 
      <type> 
        <code value="Annotation"/> 
      </type> 
      <type> 
        <code value="Attachment"/> 
      </type> 
      <type> 
        <code value="CodeableConcept"/> 
      </type> 
      <type> 
        <code value="CodeableReference"/> 
      </type> 
      <type> 
        <code value="Coding"/> 
      </type> 
      <type> 
        <code value="ContactPoint"/> 
      </type> 
      <type> 
        <code value="Count"/> 
      </type> 
      <type> 
        <code value="Distance"/> 
      </type> 
      <type> 
        <code value="Duration"/> 
      </type> 
      <type> 
        <code value="HumanName"/> 
      </type> 
      <type> 
        <code value="Identifier"/> 
      </type> 
      <type> 
        <code value="Money"/> 
      </type> 
      <type> 
        <code value="Period"/> 
      </type> 
      <type> 
        <code value="Quantity"/> 
      </type> 
      <type> 
        <code value="Range"/> 
      </type> 
      <type> 
        <code value="Ratio"/> 
      </type> 
      <type> 
        <code value="RatioRange"/> 
      </type> 
      <type> 
        <code value="Reference"/> 
      </type> 
      <type> 
        <code value="SampledData"/> 
      </type> 
      <type> 
        <code value="Signature"/> 
      </type> 
      <type> 
        <code value="Timing"/> 
      </type> 
      <type> 
        <code value="ContactDetail"/> 
      </type> 
      <type> 
        <code value="DataRequirement"/> 
      </type> 
      <type> 
        <code value="Expression"/> 
      </type> 
      <type> 
        <code value="ParameterDefinition"/> 
      </type> 
      <type> 
        <code value="RelatedArtifact"/> 
      </type> 
      <type> 
        <code value="TriggerDefinition"/> 
      </type> 
      <type> 
        <code value="UsageContext"/> 
      </type> 
      <type> 
        <code value="Availability"/> 
      </type> 
      <type> 
        <code value="ExtendedContactDetail"/> 
      </type> 
      <type> 
        <code value="Dosage"/> 
      </type> 
      <type> 
        <code value="Meta"/> 
      </type> 
      <mapping> 
        <identity value="rim"/> 
        <map value="N/A"/> 
      </mapping> 
    </element> 
  </differential> 
</StructureDefinition> 

Usage note: every effort has been made to ensure that the examples are correct and useful, but they are not a normative part of the specification.