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2.1.26.0 FHIR Type Framework

FHIR Infrastructure icon Work GroupMaturity Level: NormativeStandards Status: Normative

Types Framework Cross Reference: Base Types | Datatypes | Resources | Patterns

The FHIR specification defines types in the following general categories:

  1. Datatypes
  2. Resources
  3. Logical Models

This page defines the base abstract types that provide the foundation for all those types:

BaseElementUnique id for the element within a resource (for internal references). This may be any string value that does not contain spacesid : string [0..1]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 extensionextension : Extension [0..*]BackboneElementMay be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself) (this element modifies the meaning of other elements)modifierExtension : Extension [0..*]DataTypeResourceThe logical id of the resource, as used in the URL for the resource. Once assigned, this value never changesid : id [0..1]The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resourcemeta : Meta [0..1]A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc (this element modifies the meaning of other elements)implicitRules : uri [0..1]The base language in which the resource is writtenlanguage : code [0..1] « null (Strength=Preferred)CommonLanguages? »DomainResourceA human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safetytext : Narrative [0..1]These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, nor can they have their own independent transaction scope. This is allowed to be a Parameters resource if and only if it is referenced by a resource that provides context/meaningcontained : Resource [0..*]May be used to represent additional information that is not part of the basic definition of the resource. 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 extensionextension : Extension [0..*]May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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 is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself) (this element modifies the meaning of other elements)modifierExtension : Extension [0..*]PrimitiveTypeBackboneTypeMay be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself) (this element modifies the meaning of other elements)modifierExtension : Extension [0..*]CanonicalResource «Interface»An absolute URI that is used to identify this {{title}} when it is referenced in a specification, model, design or an instance; also called its canonical identifier. This SHOULD be globally unique and SHOULD be a literal address at which an authoritative instance of this {{title}} is (or will be) published. This URL can be the target of a canonical reference. It SHALL remain the same when the {{title}} is stored on different serversurl : uri [0..1]A formal identifier that is used to identify this {{title}} when it is represented in other formats, or referenced in a specification, model, design or an instanceidentifier : Identifier [0..*]The identifier that is used to identify this version of the {{title}} when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the {{title}} author and is not expected to be globally unique. For example, it might be a timestamp (e.g. yyyymmdd) if a managed version is not available. There is also no expectation that versions can be placed in a lexicographical sequenceversion : string [0..1]Indicates the mechanism used to compare versions to determine which is more currentversionAlgorithm[x] : DataType [0..1] « string|Coding; null (Strength=Extensible) VersionAlgorithm+ »A natural language name identifying the {{title}}. This name should be usable as an identifier for the module by machine processing applications such as code generationname : string [0..1] « This element has or is affected by some invariantsC »A short, descriptive, user-friendly title for the {{title}}title : string [0..1]The status of this {{title}}. Enables tracking the life-cycle of the content (this element modifies the meaning of other elements)status : code [1..1] « null (Strength=Required)PublicationStatus! »A Boolean value to indicate that this {{title}} is authored for testing purposes (or education/evaluation/marketing) and is not intended to be used for genuine usageexperimental : boolean [0..1]The date (and optionally time) when the {{title}} was published. The date must change when the business version changes and it must change if the status code changes. In addition, it should change when the substantive content of the {{title}} changesdate : dateTime [0..1]The name of the organization or individual responsible for the release and ongoing maintenance of the {{title}}publisher : string [0..1]Contact details to assist a user in finding and communicating with the publishercontact : ContactDetail [0..*]A free text natural language description of the {{title}} from a consumer's perspectivedescription : markdown [0..1]The content was developed with a focus and intent of supporting the contexts that are listed. These contexts may be general categories (gender, age, ...) or may be references to specific programs (insurance plans, studies, ...) and may be used to assist with indexing and searching for appropriate {{title}} instancesuseContext : UsageContext [0..*]A legal or geographic region in which the {{title}} is intended to be usedjurisdiction : CodeableConcept [0..*] « null (Strength=Extensible)JurisdictionValueSet+ »Explanation of why this {{title}} is needed and why it has been designed as it haspurpose : markdown [0..1]A copyright statement relating to the {{title}} and/or its contents. Copyright statements are generally legal restrictions on the use and publishing of the {{title}}copyright : markdown [0..1]A short string (<50 characters), suitable for inclusion in a page footer that identifies the copyright holder, effective period, and optionally whether rights are resctricted. (e.g. 'All rights reserved', 'Some rights reserved')copyrightLabel : string [0..1]MetadataResource «Interface»The date on which the resource content was approved by the publisher. Approval happens once when the content is officially approved for usageapprovalDate : date [0..1]The date on which the resource content was last reviewed. Review happens periodically after approval but does not change the original approval datelastReviewDate : date [0..1]The period during which the {{title}} content was or is planned to be in active useeffectivePeriod : Period [0..1]Descriptive topics related to the content of the {{title}}. Topics provide a high-level categorization as well as keywords for the {{title}} that can be useful for filtering and searchingtopic : CodeableConcept [0..*] « null (Strength=Example)DefinitionTopic?? »An individiual or organization primarily involved in the creation and maintenance of the {{title}}author : ContactDetail [0..*]An individual or organization primarily responsible for internal coherence of the {{title}}editor : ContactDetail [0..*]An individual or organization primarily responsible for review of some aspect of the {{title}}reviewer : ContactDetail [0..*]An individual or organization responsible for officially endorsing the {{title}} for use in some settingendorser : ContactDetail [0..*]Related artifacts such as additional documentation, justification, dependencies, bibliographic references, and predecessor and successor artifactsrelatedArtifact : RelatedArtifact [0..*]

Legend: see Standards Status Colors


FHIR Infrastructure icon Work GroupMaturity Level: 5Standards Status: Normative

See also Detailed Descriptions, Mappings, Profiles & Extensions and R4 Conversions.

The Base type that all other types specialize. This type has no properties or constraints.

UML Diagram (Legend)

Changes since Release 3

This complex-type did not exist in Release 3

UML Diagram (Legend)

Changes since Release 3

This complex-type did not exist in Release 3

Specializations:

In addition, this type is used in Logical Models that don't have or want id/extension.

Note: implementations often use this type to introduce the navigation features defined in the FHIRPath specification icon.

FHIR Infrastructure icon Work GroupMaturity Level: 5Standards Status: Normative

See also Detailed Descriptions, Mappings, Profiles & Extensions and R4 Conversions.

The base definition for all elements contained inside a resource. All elements, whether defined as a Datatype (including primitives) or as part of a resource structure, have this base content:

There are 3 kinds of descendant types that specialize Element:

Note that resources themselves all specialize the base type Resource.

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. Element«A»NBaseBase for all elements
+ Rule: All FHIR elements must have a @value or children

Elements defined in Ancestors:
... id0..1stringUnique id for inter-element referencing
... extension0..*ExtensionAdditional content defined by implementations


doco Documentation for this format

Changes since Release 3

Element
Element.id
  • Type changed from string to id
  • Type changed from string to id

See the Full Difference for further information

As the base type for all elements included in a resource, Element is an important structural element of FHIR. Even the primitive types inherit the base features and representation rules that apply to the Element type.

Constraints

idLevelLocationDescriptionExpression
img ele-1Rule (base)All FHIR elements must have a @value or childrenhasValue() or (children().count() > id.count())

This constraint exists to reduce syntactical variation in resource contents. If an element has no children, then it is always omitted from the resource, as opposed to optionally present without any content.

The id property of the element is defined to allow implementers to build implementation functionality that makes use of internal references inside the resource. This specification does not define any general use for the internal id, though some resources (e.g. StructureDefinition) and extensions (e.g. originalText, narrativeLink) make use of it.

The internal id is unique within the scope of the resource that contains it. Specifically, this means:

  • The id SHALL be unique within a given resource
  • The uniqueness boundary extends into contained resources. i.e. a contained resource cannot have the same id as any element in the resource that contains it or any other contained resource
  • The uniqueness boundary is broken at Bundle.entry.resource and Parameters.parameter.resource, since these are elements that aggregate different resources
  • The id element does not have extensions itself

These rules ensure that there is no need to change internal identifiers while exchanging resources.

FHIR Infrastructure icon Work GroupMaturity Level: 5Standards Status: Normative

See also Detailed Descriptions, Mappings, Profiles & Extensions and R4 Conversions.

The base definition for complex elements defined as part of a resource definition - that is, elements that have children that are defined in the resource. Datatype elements do not use this type. For instance, Patient.contact is an element that is defined as part of the patient resource, so it automatically has the type BackboneElement.

Note that the descendant types of BackboneElement are all declared implicitly as part of the definitions of the resources.

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. BackboneElement«A»NElementBase for elements defined inside a resource

Elements defined in Ancestors: id, extension
... modifierExtension?!Σ0..*ExtensionExtensions that cannot be ignored even if unrecognized


doco Documentation for this format

UML Diagram (Legend)

Changes since Release 3

BackboneElement
  • No Changes

See the Full Difference for further information

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. BackboneElement«A»NElementBase for elements defined inside a resource

Elements defined in Ancestors: id, extension
... modifierExtension?!Σ0..*ExtensionExtensions that cannot be ignored even if unrecognized


doco Documentation for this format

UML Diagram (Legend)

Changes since Release 3

BackboneElement
  • No Changes

See the Full Difference for further information

 

FHIR Infrastructure icon Work GroupMaturity Level: 5Standards Status: Normative

See also Detailed Descriptions, Mappings, Profiles & Extensions and R4 Conversions.

The base definition for the useable types defined by the FHIR Specification.

See FHIR Datatypes for specialization of this type.

Changes since Release 3

This complex-type did not exist in Release 3

 

FHIR Infrastructure icon Work GroupMaturity Level: 5Standards Status: Normative

See also Detailed Descriptions, Mappings, Profiles & Extensions and R4 Conversions.

The base definition for the few datatypes that allow modifier extensions:

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. BackboneType«A»NElementBase for datatypes that can carry modifier extensions

Elements defined in Ancestors: id, extension
... modifierExtension?!Σ0..*ExtensionExtensions that cannot be ignored even if unrecognized


doco Documentation for this format

Changes since Release 3

This complex-type did not exist in Release 3

 

FHIR Infrastructure icon Work GroupMaturity Level: 5Standards Status: Normative

See also Detailed Descriptions, Mappings, Profiles & Extensions and R4 Conversions.

The base type for all re-useable types defined that have a simple property. See Primitive Types for the list of defined primitives types.

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. PrimitiveType«A»NDataTypeParent type for DataTypes with a simple value

Elements defined in Ancestors: id, extension

doco Documentation for this format

Changes since Release 3

This complex-type did not exist in Release 3

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. PrimitiveType«A»NDataTypeParent type for DataTypes with a simple value

Elements defined in Ancestors: id, extension

doco Documentation for this format

Changes since Release 3

This complex-type did not exist in Release 3