Physical Activity Implementation Guide
1.0.0 - STU Release 1 United States of America flag

This page is part of the U.S. Physical Activity IG (v1.0.0: STU 1.0) based on FHIR R4. This is the current published version in its permanent home (it will always be available at this URL). For a full list of available versions, see the Directory of published versions

Data Type Profile: ReferenceRestOrLogical - XML Profile

Page standards status: Trial-use Maturity Level: 2

XML representation of the reference-rest-or-logical data type profile.

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<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="reference-rest-or-logical"/>
  <text>
    <status value="extensions"/>
    <div xmlns="http://www.w3.org/1999/xhtml">Placeholder</div>
  </text>
  <extension
             url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm">
    <valueInteger value="2">
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom">
        <valueCanonical
                        value="http://hl7.org/fhir/us/physical-activity/ImplementationGuide/physical-activity"/>
      </extension>
    </valueInteger>
  </extension>
  <extension
             url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
    <valueCode value="trial-use">
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom">
        <valueCanonical
                        value="http://hl7.org/fhir/us/physical-activity/ImplementationGuide/physical-activity"/>
      </extension>
    </valueCode>
  </extension>
  <url
       value="http://hl7.org/fhir/us/physical-activity/StructureDefinition/reference-rest-or-logical"/>
  <version value="1.0.0"/>
  <name value="ReferenceRestOrLogical"/>
  <title value="Reference - RESTful or Logical"/>
  <status value="active"/>
  <date value="2023-08-25T15:35:25+00:00"/>
  <publisher value="HL7 International - Patient Care WG"/>
  <contact>
    <name value="HL7 International - Patient Care WG"/>
    <telecom>
      <system value="url"/>
      <value value="http://www.hl7.org/Special/committees/patientcare"/>
    </telecom>
  </contact>
  <description
               value="A Reference data type where the referenced resource could be resolvable RESTfully or pointed to logically."/>
  <jurisdiction>
    <coding>
      <system value="urn:iso:std:iso:3166"/>
      <code value="US"/>
    </coding>
  </jurisdiction>
  <fhirVersion value="4.0.1"/>
  <mapping>
    <identity value="rim"/>
    <uri value="http://hl7.org/v3"/>
    <name value="RIM Mapping"/>
  </mapping>
  <kind value="complex-type"/>
  <abstract value="false"/>
  <type value="Reference"/>
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Reference"/>
  <derivation value="constraint"/>
  <snapshot>
    <element id="Reference">
      <path value="Reference"/>
      <short value="A reference from one resource to another"/>
      <definition value="A reference from one resource to another."/>
      <comment
               value="References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc.). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository."/>
      <min value="0"/>
      <max value="*"/>
      <base>
        <path value="Reference"/>
        <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="ref-1"/>
        <severity value="error"/>
        <human
               value="SHALL have a contained resource if a local reference is provided"/>
        <expression
                    value="reference.startsWith('#').not() or (reference.substring(1).trace('url') in %rootResource.contained.id.trace('ids'))"/>
        <xpath
               value="not(starts-with(f:reference/@value, '#')) or exists(ancestor::*[self::f:entry or self::f:parameter]/f:resource/f:*/f:contained/f:*[f:id/@value=substring-after(current()/f:reference/@value, '#')]|/*/f:contained/f:*[f:id/@value=substring-after(current()/f:reference/@value, '#')])"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Reference"/>
      </constraint>
      <constraint>
        <key value="PA-ident-1"/>
        <severity value="error"/>
        <human value="reference or identifier must be present"/>
        <expression value="reference.exists() or identifier.exists()"/>
        <xpath value="exists(f:reference) or exists(f:identifier)"/>
        <source
                value="http://hl7.org/fhir/us/physical-activity/StructureDefinition/reference-rest-or-logical"/>
      </constraint>
      <constraint>
        <key value="PA-ident-2"/>
        <severity value="error"/>
        <human value="If reference is not present, display must be present"/>
        <expression
                    value="reference.exists().not() implies display.exists()"/>
        <xpath value="exists(f:reference) or exists(f:display)"/>
        <source
                value="http://hl7.org/fhir/us/physical-activity/StructureDefinition/reference-rest-or-logical"/>
      </constraint>
      <isModifier value="false"/>
      <mapping>
        <identity value="rim"/>
        <map value="n/a"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map
             value="The target of a resource reference is a RIM entry point (Act, Role, or Entity)"/>
      </mapping>
    </element>
    <element id="Reference.id">
      <path value="Reference.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="Reference.extension">
      <path value="Reference.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="Reference.reference">
      <path value="Reference.reference"/>
      <short value="Literal reference, Relative, internal or absolute URL"/>
      <definition
                  value="A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources."/>
      <comment
               value="Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure &quot;/[type]/[id]&quot; then it should be assumed that the reference is to a FHIR RESTful server."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Reference.reference"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="string"/>
      </type>
      <condition value="ref-1"/>
      <condition value="PA-ident-1"/>
      <condition value="PA-ident-2"/>
      <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>
      <mustSupport value="true"/>
      <isModifier value="false"/>
      <isSummary value="true"/>
      <mapping>
        <identity value="rim"/>
        <map value="N/A"/>
      </mapping>
    </element>
    <element id="Reference.type">
      <path value="Reference.type"/>
      <short value="Type the reference refers to (e.g. &quot;Patient&quot;)"/>
      <definition
                  value="The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. &quot;Patient&quot; is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources)."/>
      <comment
               value="This element is used to indicate the type of  the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Reference.type"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="uri"/>
      </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"/>
      <binding>
        <extension
                   url="http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName">
          <valueString value="FHIRResourceTypeExt"/>
        </extension>
        <strength value="extensible"/>
        <description
                     value="Aa resource (or, for logical models, the URI of the logical model)."/>
        <valueSet value="http://hl7.org/fhir/ValueSet/resource-types"/>
      </binding>
      <mapping>
        <identity value="rim"/>
        <map value="N/A"/>
      </mapping>
    </element>
    <element id="Reference.identifier">
      <path value="Reference.identifier"/>
      <short value="Logical reference, when literal reference is not known"/>
      <definition
                  value="An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference."/>
      <comment
               value="When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy. 

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference.  For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport).  One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any)."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Reference.identifier"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="Identifier"/>
      </type>
      <condition value="PA-ident-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>
      <mustSupport value="true"/>
      <isModifier value="false"/>
      <isSummary value="true"/>
      <mapping>
        <identity value="rim"/>
        <map value=".identifier"/>
      </mapping>
    </element>
    <element id="Reference.identifier.id">
      <path value="Reference.identifier.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="Reference.identifier.extension">
      <path value="Reference.identifier.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="Reference.identifier.use">
      <path value="Reference.identifier.use"/>
      <short value="usual | official | temp | secondary | old (If known)"/>
      <definition value="The purpose of this identifier."/>
      <comment
               value="Applications can assume that an identifier is permanent unless it explicitly says that it is temporary."/>
      <requirements
                    value="Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Identifier.use"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="code"/>
      </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="true"/>
      <isModifierReason
                        value="This is labeled as &quot;Is Modifier&quot; because applications should not mistake a temporary id for a permanent one."/>
      <isSummary value="true"/>
      <binding>
        <extension
                   url="http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName">
          <valueString value="IdentifierUse"/>
        </extension>
        <strength value="required"/>
        <description
                     value="Identifies the purpose for this identifier, if known ."/>
        <valueSet value="http://hl7.org/fhir/ValueSet/identifier-use|4.0.1"/>
      </binding>
      <mapping>
        <identity value="v2"/>
        <map value="N/A"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="Role.code or implied by context"/>
      </mapping>
    </element>
    <element id="Reference.identifier.type">
      <path value="Reference.identifier.type"/>
      <short value="Description of identifier"/>
      <definition
                  value="A coded type for the identifier that can be used to determine which identifier to use for a specific purpose."/>
      <comment
               value="This element deals only with general categories of identifiers.  It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage.   Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type."/>
      <requirements
                    value="Allows users to make use of identifiers when the identifier system is not known."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Identifier.type"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="CodeableConcept"/>
      </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"/>
      <binding>
        <extension
                   url="http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName">
          <valueString value="IdentifierType"/>
        </extension>
        <extension
                   url="http://hl7.org/fhir/StructureDefinition/elementdefinition-isCommonBinding">
          <valueBoolean value="true"/>
        </extension>
        <strength value="extensible"/>
        <description
                     value="A coded type for an identifier that can be used to determine which identifier to use for a specific purpose."/>
        <valueSet value="http://hl7.org/fhir/ValueSet/identifier-type"/>
      </binding>
      <mapping>
        <identity value="v2"/>
        <map value="CX.5"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="Role.code or implied by context"/>
      </mapping>
    </element>
    <element id="Reference.identifier.system">
      <path value="Reference.identifier.system"/>
      <short value="The namespace for the identifier value"/>
      <definition
                  value="Establishes the namespace for the value - that is, a URL that describes a set values that are unique."/>
      <comment value="Identifier.system is always case sensitive."/>
      <requirements
                    value="There are many sets  of identifiers.  To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Identifier.system"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="uri"/>
      </type>
      <patternUri value="http://hl7.org/fhir/sid/us-npi"/>
      <example>
        <label value="General"/>
        <valueUri value="http://www.acme.com/identifiers/patient"/>
      </example>
      <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="v2"/>
        <map value="CX.4 / EI-2-4"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="II.root or Role.id.root"/>
      </mapping>
      <mapping>
        <identity value="servd"/>
        <map value="./IdentifierType"/>
      </mapping>
    </element>
    <element id="Reference.identifier.value">
      <path value="Reference.identifier.value"/>
      <short value="The value that is unique"/>
      <definition
                  value="The portion of the identifier typically relevant to the user and which is unique within the context of the system."/>
      <comment
               value="If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986.  The value's primary purpose is computational mapping.  As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.)  A value formatted for human display can be conveyed using the [Rendered Value extension](http://hl7.org/fhir/R4/extension-rendered-value.html). Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe."/>
      <min value="1"/>
      <max value="1"/>
      <base>
        <path value="Identifier.value"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="string"/>
      </type>
      <example>
        <label value="General"/>
        <valueString value="123456"/>
      </example>
      <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>
      <mustSupport value="true"/>
      <isModifier value="false"/>
      <isSummary value="true"/>
      <mapping>
        <identity value="v2"/>
        <map value="CX.1 / EI.1"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map
             value="II.extension or II.root if system indicates OID or GUID (Or Role.id.extension or root)"/>
      </mapping>
      <mapping>
        <identity value="servd"/>
        <map value="./Value"/>
      </mapping>
    </element>
    <element id="Reference.identifier.period">
      <path value="Reference.identifier.period"/>
      <short value="Time period when id is/was valid for use"/>
      <definition
                  value="Time period during which identifier is/was valid for use."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Identifier.period"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="Period"/>
      </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="v2"/>
        <map value="CX.7 + CX.8"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="Role.effectiveTime or implied by context"/>
      </mapping>
      <mapping>
        <identity value="servd"/>
        <map value="./StartDate and ./EndDate"/>
      </mapping>
    </element>
    <element id="Reference.identifier.assigner">
      <path value="Reference.identifier.assigner"/>
      <short value="Organization that issued id (may be just text)"/>
      <definition value="Organization that issued/manages the identifier."/>
      <comment
               value="The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Identifier.assigner"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="Reference"/>
        <targetProfile
                       value="http://hl7.org/fhir/StructureDefinition/Organization"/>
      </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="v2"/>
        <map value="CX.4 / (CX.4,CX.9,CX.10)"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map
             value="II.assigningAuthorityName but note that this is an improper use by the definition of the field.  Also Role.scoper"/>
      </mapping>
      <mapping>
        <identity value="servd"/>
        <map value="./IdentifierIssuingAuthority"/>
      </mapping>
    </element>
    <element id="Reference.display">
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/elementdefinition-translatable">
        <valueBoolean value="true"/>
      </extension>
      <path value="Reference.display"/>
      <short value="Text alternative for the resource"/>
      <definition
                  value="Plain text narrative that identifies the resource in addition to the resource reference."/>
      <comment
               value="This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Reference.display"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="string"/>
      </type>
      <condition value="PA-ident-2"/>
      <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>
      <mustSupport value="true"/>
      <isModifier value="false"/>
      <isSummary value="true"/>
      <mapping>
        <identity value="rim"/>
        <map value="N/A"/>
      </mapping>
    </element>
  </snapshot>
  <differential>
    <element id="Reference">
      <path value="Reference"/>
      <constraint>
        <key value="PA-ident-1"/>
        <severity value="error"/>
        <human value="reference or identifier must be present"/>
        <expression value="reference.exists() or identifier.exists()"/>
        <xpath value="exists(f:reference) or exists(f:identifier)"/>
        <source
                value="http://hl7.org/fhir/us/physical-activity/StructureDefinition/reference-rest-or-logical"/>
      </constraint>
      <constraint>
        <key value="PA-ident-2"/>
        <severity value="error"/>
        <human value="If reference is not present, display must be present"/>
        <expression
                    value="reference.exists().not() implies display.exists()"/>
        <xpath value="exists(f:reference) or exists(f:display)"/>
        <source
                value="http://hl7.org/fhir/us/physical-activity/StructureDefinition/reference-rest-or-logical"/>
      </constraint>
    </element>
    <element id="Reference.reference">
      <path value="Reference.reference"/>
      <condition value="PA-ident-1"/>
      <condition value="PA-ident-2"/>
      <mustSupport value="true"/>
    </element>
    <element id="Reference.identifier">
      <path value="Reference.identifier"/>
      <condition value="PA-ident-1"/>
      <mustSupport value="true"/>
    </element>
    <element id="Reference.identifier.system">
      <path value="Reference.identifier.system"/>
      <patternUri value="http://hl7.org/fhir/sid/us-npi"/>
    </element>
    <element id="Reference.identifier.value">
      <path value="Reference.identifier.value"/>
      <min value="1"/>
      <mustSupport value="true"/>
    </element>
    <element id="Reference.display">
      <path value="Reference.display"/>
      <condition value="PA-ident-2"/>
      <mustSupport value="true"/>
    </element>
  </differential>
</StructureDefinition>