FHIR Extensions Pack
5.2.0-ballot - 5.2.0 Ballot - September 2024) International flag

FHIR Extensions Pack, published by HL7 International / FHIR Infrastructure. This guide is not an authorized publication; it is the continuous build for version 5.2.0-ballot built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/fhir-extensions/ and changes regularly. See the Directory of published versions

Extension: TargetInvariant - Detailed Descriptions

Page standards status: Deprecated Maturity Level: 2

Definitions for the cqf-targetInvariant extension.

Guidance on how to interpret the contents of this table can be found here

0. Extension
Definition

Specifies an invariant that is enforced in the context of an instantiated resource.

ShortA constraint on the target resource
Comments

Can be used on any definitional artifact to define an invariant that is enforced in the context of an instantiated resource. The invariant expression will have access to %target and %definition variables, where target is the instantiated resource, and definition is the definition used to instantiate.

Control0..*
2. Extension.extension:key
Slice Namekey
Definition

A unique identifier for the invariant (unique in the context of the resource).

ShortUnique identifier
Comments

Any error or outcome messages or warnings should include this id to allow the source of the message to be determined.

Control1..1
TypeExtension
4. Extension.extension:key.extension
Control0..0
6. Extension.extension:key.url
Typeuri
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Fixed Valuekey
8. Extension.extension:key.value[x]
Control1..?
Typeid
[x] NoteSeeChoice of Data Typesfor further information about how to use [x]
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
10. Extension.extension:requirements
Slice Namerequirements
Definition

A brief description of why the invariant is necessary or appropriate.

ShortWhy the invariant is defined
Control0..1
TypeExtension
12. Extension.extension:requirements.extension
Control0..0
14. Extension.extension:requirements.url
Typeuri
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Fixed Valuerequirements
16. Extension.extension:requirements.value[x]
Control1..?
Typestring
[x] NoteSeeChoice of Data Typesfor further information about how to use [x]
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
18. Extension.extension:severity
Slice Nameseverity
Definition

Whether the invariant indicates an error condition or a warning.

Shorterror | warning
Control1..1
TypeExtension
20. Extension.extension:severity.extension
Control0..0
22. Extension.extension:severity.url
Typeuri
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Fixed Valueseverity
24. Extension.extension:severity.value[x]
Control1..?
BindingThe codes SHALL be taken from ConstraintSeverity
(required to http://hl7.org/fhir/ValueSet/constraint-severity)
Typecode
[x] NoteSeeChoice of Data Typesfor further information about how to use [x]
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
26. Extension.extension:expression
Slice Nameexpression
Definition

An expression providing a formal representation of the invariant condition.

ShortThe invariant expression
Comments

The expression will have access to %target (the resource that was instantiated) and %definition (the definition for the instantiated resource).

Control1..1
TypeExtension
28. Extension.extension:expression.extension
Control0..0
30. Extension.extension:expression.url
Typeuri
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Fixed Valueexpression
32. Extension.extension:expression.value[x]
Control1..?
TypeExpression
[x] NoteSeeChoice of Data Typesfor further information about how to use [x]
34. Extension.url
Fixed Valuehttp://hl7.org/fhir/StructureDefinition/cqf-targetInvariant
36. Extension.value[x]
Control0..0

Guidance on how to interpret the contents of this table can be found here

0. Extension
Definition

Specifies an invariant that is enforced in the context of an instantiated resource.


Optional Extension Element - found in all resources.

ShortA constraint on the target resourceOptional Extensions Element
Comments

Can be used on any definitional artifact to define an invariant that is enforced in the context of an instantiated resource. The invariant expression will have access to %target and %definition variables, where target is the instantiated resource, and definition is the definition used to instantiate.

Control0..*
Is Modifierfalse
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
2. Extension.extension
Definition

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 managable, 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.

ShortAdditional content defined by implementations
Comments

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.

Controlicon Changed:30..*
TypeExtension
Is Modifierfalse
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
SlicingThis element introduces a set of slices on Extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ url
  • 4. Extension.extension:key
    Slice Namekey
    Definition

    A unique identifier for the invariant (unique in the context of the resource).

    ShortUnique identifierAdditional content defined by implementations
    Comments

    Any error or outcome messages or warnings should include this id to allow the source of the message to be determined.

    Control10..1*
    TypeExtension
    Is Modifierfalse
    Summaryfalse
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    6. Extension.extension:key.extension
    Definition

    An Extension


    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 managable, 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.

    ShortExtensionAdditional content defined by implementations
    Comments

    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.

    Control0..0*
    TypeExtension
    Is Modifierfalse
    Summaryfalse
    Alternate Namesextensions, user content
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    SlicingThis element introduces a set of slices on Extension.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • value @ url
    • 8. Extension.extension:key.url
      Definition

      Source of the definition for the extension code - a logical name or a URL.

      Shortidentifies the meaning of the extension
      Comments

      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.

      Control1..1
      Typeuri
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      XML FormatIn the XML format, this property is represented as an attribute.
      Summaryfalse
      Fixed Valuekey
      10. Extension.extension:key.value[x]
      Definition

      Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

      ShortValue of extension
      Control10..1
      This element is affected by the following invariants: ext-1
      Typeid, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, RatioRange, Coding, SampledData, positiveInt, Distance, Availability, integer64, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, ExtendedContactDetail, CodeableConcept, ParameterDefinition, dateTime, code, string, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Expression, CodeableReference, Signature, unsignedInt, time
      [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      12. Extension.extension:requirements
      Slice Namerequirements
      Definition

      A brief description of why the invariant is necessary or appropriate.

      ShortWhy the invariant is definedAdditional content defined by implementations
      Control0..1*
      TypeExtension
      Is Modifierfalse
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      14. Extension.extension:requirements.extension
      Definition

      An Extension


      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 managable, 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.

      ShortExtensionAdditional content defined by implementations
      Comments

      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.

      Control0..0*
      TypeExtension
      Is Modifierfalse
      Summaryfalse
      Alternate Namesextensions, user content
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      SlicingThis element introduces a set of slices on Extension.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
      • value @ url
      • 16. Extension.extension:requirements.url
        Definition

        Source of the definition for the extension code - a logical name or a URL.

        Shortidentifies the meaning of the extension
        Comments

        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.

        Control1..1
        Typeuri
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        XML FormatIn the XML format, this property is represented as an attribute.
        Summaryfalse
        Fixed Valuerequirements
        18. Extension.extension:requirements.value[x]
        Definition

        Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

        ShortValue of extension
        Control10..1
        This element is affected by the following invariants: ext-1
        Typestring, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, RatioRange, Coding, SampledData, id, positiveInt, Distance, Availability, integer64, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, ExtendedContactDetail, CodeableConcept, ParameterDefinition, dateTime, code, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Expression, CodeableReference, Signature, unsignedInt, time
        [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        20. Extension.extension:severity
        Slice Nameseverity
        Definition

        Whether the invariant indicates an error condition or a warning.

        Shorterror | warningAdditional content defined by implementations
        Control10..1*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        22. Extension.extension:severity.extension
        Definition

        An Extension


        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 managable, 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.

        ShortExtensionAdditional content defined by implementations
        Comments

        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.

        Control0..0*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        SlicingThis element introduces a set of slices on Extension.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
        • value @ url
        • 24. Extension.extension:severity.url
          Definition

          Source of the definition for the extension code - a logical name or a URL.

          Shortidentifies the meaning of the extension
          Comments

          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.

          Control1..1
          Typeuri
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          XML FormatIn the XML format, this property is represented as an attribute.
          Summaryfalse
          Fixed Valueseverity
          26. Extension.extension:severity.value[x]
          Definition

          Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

          ShortValue of extension
          Control10..1
          This element is affected by the following invariants: ext-1
          BindingThe codes SHALL be taken from For codes, see ConstraintSeverity
          (required to http://hl7.org/fhir/ValueSet/constraint-severity)
          Typecode, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, RatioRange, Coding, SampledData, id, positiveInt, Distance, Availability, integer64, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, ExtendedContactDetail, CodeableConcept, ParameterDefinition, dateTime, string, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Expression, CodeableReference, Signature, unsignedInt, time
          [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Summaryfalse
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          28. Extension.extension:expression
          Slice Nameexpression
          Definition

          An expression providing a formal representation of the invariant condition.

          ShortThe invariant expressionAdditional content defined by implementations
          Comments

          The expression will have access to %target (the resource that was instantiated) and %definition (the definition for the instantiated resource).

          Control10..1*
          TypeExtension
          Is Modifierfalse
          Summaryfalse
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
          30. Extension.extension:expression.extension
          Definition

          An Extension


          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 managable, 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.

          ShortExtensionAdditional content defined by implementations
          Comments

          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.

          Control0..0*
          TypeExtension
          Is Modifierfalse
          Summaryfalse
          Alternate Namesextensions, user content
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
          SlicingThis element introduces a set of slices on Extension.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
          • value @ url
          • 32. Extension.extension:expression.url
            Definition

            Source of the definition for the extension code - a logical name or a URL.

            Shortidentifies the meaning of the extension
            Comments

            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.

            Control1..1
            Typeuri
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            XML FormatIn the XML format, this property is represented as an attribute.
            Summaryfalse
            Fixed Valueexpression
            34. Extension.extension:expression.value[x]
            Definition

            Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

            ShortValue of extension
            Control10..1
            This element is affected by the following invariants: ext-1
            TypeExpression, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, RatioRange, Coding, SampledData, id, positiveInt, Distance, Availability, integer64, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, ExtendedContactDetail, CodeableConcept, ParameterDefinition, dateTime, code, string, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, CodeableReference, Signature, unsignedInt, time
            [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
            Is Modifierfalse
            Summaryfalse
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            36. Extension.url
            Definition

            Source of the definition for the extension code - a logical name or a URL.

            Shortidentifies the meaning of the extension
            Comments

            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.

            Control1..1
            Typeuri
            Is Modifierfalse
            XML FormatIn the XML format, this property is represented as an attribute.
            Summaryfalse
            Fixed Valuehttp://hl7.org/fhir/StructureDefinition/cqf-targetInvariant
            38. Extension.value[x]
            Definition

            Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

            ShortValue of extension
            Control0..01
            This element is affected by the following invariants: ext-1
            TypeChoice of: base64Binary, boolean, canonical, code, date, dateTime, decimal, id, instant, integer, integer64, markdown, oid, positiveInt, string, time, unsignedInt, uri, url, uuid, Address, Age, Annotation, Attachment, CodeableConcept, CodeableReference, Coding, ContactPoint, Count, Distance, Duration, HumanName, Identifier, Money, Period, Quantity, Range, Ratio, RatioRange, Reference, SampledData, Signature, Timing, ContactDetail, DataRequirement, Expression, ParameterDefinition, RelatedArtifact, TriggerDefinition, UsageContext, Availability, ExtendedContactDetail, Dosage, Meta
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Summaryfalse
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))

            Guidance on how to interpret the contents of this table can be found here

            0. Extension
            Definition

            Specifies an invariant that is enforced in the context of an instantiated resource.

            ShortA constraint on the target resource
            Comments

            Can be used on any definitional artifact to define an invariant that is enforced in the context of an instantiated resource. The invariant expression will have access to %target and %definition variables, where target is the instantiated resource, and definition is the definition used to instantiate.

            Control0..*
            Is Modifierfalse
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
            2. Extension.id
            Definition

            Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

            ShortUnique id for inter-element referencing
            Control0..1
            This element is affected by the following invariants: ele-1
            Typeid
            Is Modifierfalse
            XML FormatIn the XML format, this property is represented as an attribute.
            Summaryfalse
            4. Extension.extension
            Definition

            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 managable, 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.

            ShortAdditional content defined by implementations
            Comments

            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.

            Controlicon Changed:3..*
            TypeExtension
            Is Modifierfalse
            Summaryfalse
            Alternate Namesextensions, user content
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
            SlicingThis element introduces a set of slices on Extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
            • value @ url
            • 6. Extension.extension:key
              Slice Namekey
              Definition

              A unique identifier for the invariant (unique in the context of the resource).

              ShortUnique identifier
              Comments

              Any error or outcome messages or warnings should include this id to allow the source of the message to be determined.

              Control1..1
              TypeExtension
              Is Modifierfalse
              Summaryfalse
              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
              ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
              8. Extension.extension:key.id
              Definition

              Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

              ShortUnique id for inter-element referencing
              Control0..1
              This element is affected by the following invariants: ele-1
              Typeid
              Is Modifierfalse
              XML FormatIn the XML format, this property is represented as an attribute.
              Summaryfalse
              10. Extension.extension:key.extension
              Definition

              An Extension

              ShortExtension
              Control0..0
              TypeExtension
              Is Modifierfalse
              Summaryfalse
              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
              ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
              SlicingThis element introduces a set of slices on Extension.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
              • value @ url
              • 12. Extension.extension:key.url
                Definition

                Source of the definition for the extension code - a logical name or a URL.

                Shortidentifies the meaning of the extension
                Comments

                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.

                Control1..1
                Typeuri
                Is Modifierfalse
                Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                XML FormatIn the XML format, this property is represented as an attribute.
                Summaryfalse
                Fixed Valuekey
                14. Extension.extension:key.value[x]
                Definition

                Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

                ShortValue of extension
                Control1..1
                This element is affected by the following invariants: ext-1
                Typeid
                [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                Is Modifierfalse
                Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                Summaryfalse
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                16. Extension.extension:requirements
                Slice Namerequirements
                Definition

                A brief description of why the invariant is necessary or appropriate.

                ShortWhy the invariant is defined
                Control0..1
                TypeExtension
                Is Modifierfalse
                Summaryfalse
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                18. Extension.extension:requirements.id
                Definition

                Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                ShortUnique id for inter-element referencing
                Control0..1
                This element is affected by the following invariants: ele-1
                Typeid
                Is Modifierfalse
                XML FormatIn the XML format, this property is represented as an attribute.
                Summaryfalse
                20. Extension.extension:requirements.extension
                Definition

                An Extension

                ShortExtension
                Control0..0
                TypeExtension
                Is Modifierfalse
                Summaryfalse
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                SlicingThis element introduces a set of slices on Extension.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                • value @ url
                • 22. Extension.extension:requirements.url
                  Definition

                  Source of the definition for the extension code - a logical name or a URL.

                  Shortidentifies the meaning of the extension
                  Comments

                  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.

                  Control1..1
                  Typeuri
                  Is Modifierfalse
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  XML FormatIn the XML format, this property is represented as an attribute.
                  Summaryfalse
                  Fixed Valuerequirements
                  24. Extension.extension:requirements.value[x]
                  Definition

                  Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

                  ShortValue of extension
                  Control1..1
                  This element is affected by the following invariants: ext-1
                  Typestring
                  [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                  Is Modifierfalse
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Summaryfalse
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  26. Extension.extension:severity
                  Slice Nameseverity
                  Definition

                  Whether the invariant indicates an error condition or a warning.

                  Shorterror | warning
                  Control1..1
                  TypeExtension
                  Is Modifierfalse
                  Summaryfalse
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                  28. Extension.extension:severity.id
                  Definition

                  Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                  ShortUnique id for inter-element referencing
                  Control0..1
                  This element is affected by the following invariants: ele-1
                  Typeid
                  Is Modifierfalse
                  XML FormatIn the XML format, this property is represented as an attribute.
                  Summaryfalse
                  30. Extension.extension:severity.extension
                  Definition

                  An Extension

                  ShortExtension
                  Control0..0
                  TypeExtension
                  Is Modifierfalse
                  Summaryfalse
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                  SlicingThis element introduces a set of slices on Extension.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                  • value @ url
                  • 32. Extension.extension:severity.url
                    Definition

                    Source of the definition for the extension code - a logical name or a URL.

                    Shortidentifies the meaning of the extension
                    Comments

                    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.

                    Control1..1
                    Typeuri
                    Is Modifierfalse
                    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                    XML FormatIn the XML format, this property is represented as an attribute.
                    Summaryfalse
                    Fixed Valueseverity
                    34. Extension.extension:severity.value[x]
                    Definition

                    Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

                    ShortValue of extension
                    Control1..1
                    This element is affected by the following invariants: ext-1
                    BindingThe codes SHALL be taken from ConstraintSeverity
                    (required to http://hl7.org/fhir/ValueSet/constraint-severity)
                    Typecode
                    [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                    Is Modifierfalse
                    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                    Summaryfalse
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    36. Extension.extension:expression
                    Slice Nameexpression
                    Definition

                    An expression providing a formal representation of the invariant condition.

                    ShortThe invariant expression
                    Comments

                    The expression will have access to %target (the resource that was instantiated) and %definition (the definition for the instantiated resource).

                    Control1..1
                    TypeExtension
                    Is Modifierfalse
                    Summaryfalse
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                    38. Extension.extension:expression.id
                    Definition

                    Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                    ShortUnique id for inter-element referencing
                    Control0..1
                    This element is affected by the following invariants: ele-1
                    Typeid
                    Is Modifierfalse
                    XML FormatIn the XML format, this property is represented as an attribute.
                    Summaryfalse
                    40. Extension.extension:expression.extension
                    Definition

                    An Extension

                    ShortExtension
                    Control0..0
                    TypeExtension
                    Is Modifierfalse
                    Summaryfalse
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                    SlicingThis element introduces a set of slices on Extension.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                    • value @ url
                    • 42. Extension.extension:expression.url
                      Definition

                      Source of the definition for the extension code - a logical name or a URL.

                      Shortidentifies the meaning of the extension
                      Comments

                      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.

                      Control1..1
                      Typeuri
                      Is Modifierfalse
                      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                      XML FormatIn the XML format, this property is represented as an attribute.
                      Summaryfalse
                      Fixed Valueexpression
                      44. Extension.extension:expression.value[x]
                      Definition

                      Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

                      ShortValue of extension
                      Control1..1
                      This element is affected by the following invariants: ext-1
                      TypeExpression
                      [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                      Is Modifierfalse
                      Summaryfalse
                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                      46. Extension.url
                      Definition

                      Source of the definition for the extension code - a logical name or a URL.

                      Shortidentifies the meaning of the extension
                      Comments

                      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.

                      Control1..1
                      Typeuri
                      Is Modifierfalse
                      XML FormatIn the XML format, this property is represented as an attribute.
                      Summaryfalse
                      Fixed Valuehttp://hl7.org/fhir/StructureDefinition/cqf-targetInvariant
                      48. Extension.value[x]
                      Definition

                      icon Changed:

                      Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

                      ShortValue of extension
                      Control0..0
                      This element is affected by the following invariants: ext-1
                      TypeChoice of: base64Binary, boolean, canonical, code, date, dateTime, decimal, id, instant, integer, integer64, markdown, oid, positiveInt, string, time, unsignedInt, uri, url, uuid, Address, Age, Annotation, Attachment, CodeableConcept, CodeableReference, Coding, ContactPoint, Count, Distance, Duration, HumanName, Identifier, Money, Period, Quantity, Range, Ratio, RatioRange, Reference, SampledData, Signature, Timing, ContactDetail, DataRequirement, Expression, ParameterDefinition, RelatedArtifact, TriggerDefinition, UsageContext, Availability, ExtendedContactDetail, Dosage, Meta
                      Is Modifierfalse
                      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                      Summaryfalse
                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))