Release 5 R4 Ballot #2 (Mixed Normative/Trial use)

This page is part of the FHIR Specification (v5.0.0: R5 - STU ). This is the (v3.5.0: R4 Ballot #2). The current published version. version which supercedes this version is 5.0.0 . For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B R4 R3 R2

5.4.9 5.3.8 Resource StructureDefinition - Detailed Descriptions

FHIR Infrastructure Work Group Maturity Level : N 5   Normative (from v4.0.0) Security Category : Anonymous Compartments : No Not linked to any defined compartments

Detailed Descriptions for the elements in the StructureDefinition resource.

Standards Status This element has a standards status of "Deprecated" which is different from the status of the whole resource Summary false Comments ... StructureDefinition.copyrightLabel Element Id StructureDefinition.copyrightLabel Definition 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'). Short Display Copyright holder and year(s) Cardinality 0..1 Type string Requirements Defines the content expected to be rendered in all representations of the artifact. Summary false Comments The (c) symbol should NOT be included in this string. It will be added by software when rendering the notation. Full details about licensing, restrictions, warrantees, etc. goes in the more general 'copyright' element. Standards Status This element has a standards status of "Deprecated" which is different from the status of the whole resource Use the artifact-topic extension instead Comments Note that this element is deprecated. Use the http://hl7.org/fhir/StructureDefinition/artifact-topic extension instead. Summary false Invariants Affect this element sdf-15a Rule If the first element in a differential has no "." in the path and it's not a logical model, it has no type (kind!='logical' and differential.element.first().path.contains('.').not()) implies differential.element.first().type.empty() sdf-15 Rule The first element in a snapshot has no type unless model is a logical model. kind!='logical' implies snapshot.element.first().type.empty() sdf-11 Rule If there's a type, its content must match the path name in the first element of a snapshot kind != 'logical' implies snapshot.empty() or snapshot.element.first().path = type sdf-29 Warning Elements in Resources must have a min cardinality or 0 or 1 and a max cardinality of 1 or * ((kind in 'resource' | 'complex-type') and (derivation = 'specialization')) implies differential.element.where((min != 0 and min != 1) or (max != '1' and max != '*')).empty() sdf-8 Rule All snapshot elements must start with the StructureDefinition's specified type for non-logical models, or with the same type name for logical models (%resource.kind = 'logical' or element.first().path = %resource.type) and element.tail().all(path.startsWith(%resource.snapshot.element.first().path&'.')) sdf-3 Rule Each element definition in a snapshot must have a formal definition and cardinalities, unless model is a logical model %resource.kind = 'logical' or element.all(definition.exists() and min.exists() and max.exists()) sdf-8a Rule In any differential, all the elements must start with the StructureDefinition's specified type for non-logical models, or with the same type name for logical models (%resource.kind = 'logical' or element.first().path.startsWith(%resource.type)) and (element.tail().empty() or element.tail().all(path.startsWith(%resource.differential.element.first().path.replaceMatches('\\..*','')&'.'))) Invariants Affect this element sdf-4 Rule If the structure is not abstract, then there SHALL be a baseDefinition abstract = true or baseDefinition.exists() Invariants Affect this element sdf-1 Rule Element paths must be unique unless the structure is a constraint derivation = 'constraint' or snapshot.element.select(path).isDistinct() sdf-21 Rule Default values can only be specified on specializations differential.element.defaultValue.exists() implies (derivation = 'specialization') sdf-5 Rule If the structure defines an extension then the structure must have context information type != 'Extension' or derivation = 'specialization' or (context.exists()) sdf-27 Rule If there's a base definition, there must be a derivation baseDefinition.exists() implies derivation.exists() sdf-29 Warning Elements in Resources must have a min cardinality or 0 or 1 and a max cardinality of 1 or * ((kind in 'resource' | 'complex-type') and (derivation = 'specialization')) implies differential.element.where((min != 0 and min != 1) or (max != '1' and max != '*')).empty() Summary false Invariants Affect this element sdf-9 Rule In any snapshot or differential, no label, code or requirements on an element without a "." in the path (e.g. the first element) children().element.where(path.contains('.').not()).label.empty() and children().element.where(path.contains('.').not()).code.empty() and children().element.where(path.contains('.').not()).requirements.empty() sdf-15a Rule If the first element in a differential has no "." in the path and it's not a logical model, it has no type (kind!='logical' and differential.element.first().path.contains('.').not()) implies differential.element.first().type.empty() sdf-19 Rule FHIR Specification models only use FHIR defined types url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (differential | snapshot).element.type.code.all(matches('^[a-zA-Z0-9]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$')) sdf-17 Rule All element definitions must have unique ids (diff) differential.element.all(id.exists()) and differential.element.id.trace('ids').isDistinct() sdf-23 Rule No slice name on root (snapshot | differential).element.all(path.contains('.').not() implies sliceName.empty()) sdf-22 Rule FHIR Specification models never have default values url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (snapshot.element.defaultValue.empty() and differential.element.defaultValue.empty()) sdf-14 Rule All element definitions must have an id snapshot.element.all(id.exists()) and differential.element.all(id.exists()) sdf-21 Rule Default values can only be specified on specializations differential.element.defaultValue.exists() implies (derivation = 'specialization') sdf-29 Warning Elements in Resources must have a min cardinality or 0 or 1 and a max cardinality of 1 or * ((kind in 'resource' | 'complex-type') and (derivation = 'specialization')) implies differential.element.where((min != 0 and min != 1) or (max != '1' and max != '*')).empty() sdf-20 Rule No slicing on the root element element.where(path.contains('.').not()).slicing.empty() sdf-8a Rule In any differential, all the elements must start with the StructureDefinition's specified type for non-logical models, or with the same type name for logical models (%resource.kind = 'logical' or element.first().path.startsWith(%resource.type)) and (element.tail().empty() or element.tail().all(path.startsWith(%resource.differential.element.first().path.replaceMatches('\\..*','')&'.')))
StructureDefinition
Element Id StructureDefinition
Definition

A definition of a FHIR structure. This resource is used to describe the underlying resources, data types defined in FHIR, and also for describing extensions and constraints on resources and data types.

Short Display Structural Definition Cardinality Control 0..* 1..1
Type CanonicalResource DomainResource
Alternate Names Template; Profile
Summary false Invariants sdf-27 Rule If there's a base definition, there must be a derivation baseDefinition.exists() implies derivation.exists() sdf-29 Warning Elements in Resources must have a min cardinality or 0 or 1 and a max cardinality of 1 or * ((kind in 'resource' | 'complex-type') and (derivation = 'specialization')) implies differential.element.where((min != 0 and min != 1) or (max != '1' and max != '*')).empty()
Defined on this element
cnl-0 sdf-0 Warning Name should be usable as an identifier for the module by machine processing applications such as code generation name.exists() implies name.matches('^[A-Z]([A-Za-z0-9_]){1,254}$') name.matches('[A-Z]([A-Za-z0-9_]){0,254}')
sdf-1 Rule Element paths must be unique unless the structure is a constraint derivation = 'constraint' or snapshot.element.select(path).isDistinct()
sdf-15a Rule If the first element in a differential has no "." in the path and it's not a logical model, it has no type (kind!='logical' and differential.element.first().path.contains('.').not()) implies differential.element.first().type.empty()
sdf-4 Rule If the structure is not abstract, then there SHALL be a baseDefinition abstract = true or baseDefinition.exists()
sdf-5 Rule If the structure defines an extension then the structure must have context information type != 'Extension' or derivation = 'specialization' or (context.exists())
sdf-6 Rule A structure must have either a differential, or a snapshot (or both) snapshot.exists() or differential.exists()
sdf-9 Rule In any snapshot or differential, no label, code or requirements on an element without a "." in the path (e.g. the first element) children().element.where(path.contains('.').not()).label.empty() and children().element.where(path.contains('.').not()).code.empty() and children().element.where(path.contains('.').not()).requirements.empty()
sdf-11 Rule If there's a type, its content must match the path name in the first element of a snapshot kind != 'logical' implies snapshot.empty() or snapshot.element.first().path = type
sdf-14 Rule All element definitions must have an id snapshot.element.all(id.exists()) and differential.element.all(id.exists())
sdf-15 Rule The first element in a snapshot has no type unless model is a logical model. kind!='logical' implies snapshot.element.first().type.empty()
sdf-15a Rule If the first element in a differential has no "." in the path and it's not a logical model, it has no type (kind!='logical' and differential.element.first().path.contains('.').not()) implies differential.element.first().type.empty() sdf-9 Rule In any snapshot or differential, no label, code or requirements on an element without a "." in the path (e.g. the first element) children().element.where(path.contains('.').not()).label.empty() and children().element.where(path.contains('.').not()).code.empty() and children().element.where(path.contains('.').not()).requirements.empty() sdf-16 Rule All element definitions must have unique ids (snapshot) snapshot.element.all(id.exists()) snapshot.element.all(id) and snapshot.element.id.trace('ids').isDistinct()
sdf-17 Rule All element definitions must have unique ids (diff) differential.element.all(id.exists()) differential.element.all(id) and differential.element.id.trace('ids').isDistinct()
sdf-18 Rule Context Invariants can only be used for extensions contextInvariant.exists() implies type = 'Extension'
sdf-19 Rule FHIR Specification models only use FHIR defined types url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (differential | snapshot).element.type.code.all(matches('^[a-zA-Z0-9]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$')) (differential.element.type.code.all(hasValue() implies matches('^[a-zA-Z0-9]+$')) and snapshot.element.type.code.all(hasValue() implies matches('^[a-zA-Z0-9]+$')))
sdf-21 Rule Default values can only be specified on specializations differential.element.defaultValue.exists() implies (derivation = 'specialization')
sdf-22 Rule FHIR Specification models never have default values url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (snapshot.element.defaultValue.empty() and differential.element.defaultValue.empty())
sdf-23 Rule No slice name on root (snapshot | differential).element.all(path.contains('.').not() implies sliceName.empty())
StructureDefinition.url
Element Id StructureDefinition.url
Definition

An absolute URI that is used to identify this structure definition 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 at which an authoritative instance of this structure definition is (or will be) published. This URL can be the target of a canonical reference. It SHALL remain the same when the structure definition is stored on different servers.

Short Display Canonical identifier for this structure definition, represented as a URI (globally unique) Cardinality Control 1..1
Type uri
Requirements

Allows the structure definition to be referenced by a single globally unique identifier.

Alternate Names url; authoritative-url; destination; identity
Summary true
Comments

Can be a urn:uuid: or a urn:oid: but real http: addresses are preferred. Multiple instances may share the same URL if they have a distinct version.

The determination of when to create a new version of a resource (same url, new version) vs. defining a new artifact is up to the author. Considerations for making this decision are found in Technical and Business Versions .

In some cases, the resource can no longer be found at the stated url, but the url itself cannot change. Implementations can use the meta.source element to indicate where the current master source of the resource can be found. Invariants Defined on this element cnl-1 Warning URL should not contain | or # - these characters make processing canonical references problematic exists() implies matches('^[^|# ]+$') Affect this element sdf-19 Rule FHIR Specification models only use FHIR defined types url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (differential | snapshot).element.type.code.all(matches('^[a-zA-Z0-9]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$')) sdf-22 Rule FHIR Specification models never have default values url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (snapshot.element.defaultValue.empty() and differential.element.defaultValue.empty())
StructureDefinition.identifier
Element Id StructureDefinition.identifier
Definition

A formal identifier that is used to identify this structure definition when it is represented in other formats, or referenced in a specification, model, design or an instance.

Short Display Additional identifier for the structure definition Note This is a business identifier, identifer, not a resource identifier (see discussion )
Cardinality Control 0..*
Type Identifier
Requirements

Allows externally provided and/or usable business identifiers to be easily associated with the module.

Summary true
Comments

Typically, this is used for identifiers that can go in an HL7 V3 II (instance identifier) data type, and can then identify this structure definition outside of FHIR, where it is not possible to use the logical URI.

StructureDefinition.version
Element Id StructureDefinition.version
Definition

The identifier that is used to identify this version of the structure definition when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the structure definition 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 sequence, so authors are encouraged to populate the StructureDefinition.versionAlgorithm[x] element to enable comparisons. If there is no managed version available, authors can consider using ISO date/time syntax (e.g., '2023-01-01'). sequence.

Short Display Business version of the structure definition Note This is a business versionId, not a resource version id (see discussion )
Cardinality Control 0..1
Type string
Summary true
Comments

There may be different structure definition instances that have the same identifier but different versions. The version can be appended to the url in a reference to allow a reference to a particular business version of the structure definition with the format [url]|[version]. The version SHOULD NOT contain a '#' - see Business Version . StructureDefinition.versionAlgorithm[x] Element Id StructureDefinition.versionAlgorithm[x] Definition Indicates the mechanism used to compare versions to determine which is more current. Short Display How to compare versions Cardinality 0..1 Terminology Binding Version Algorithm ( Extensible ) Type string | Coding [x] Note See Choice of Datatypes for further information about how to use [x] Summary true Comments If set as a string, this is a FHIRPath expression that has two additional context variables passed in - %version1 and %version2 and will return a negative number if version1 is newer, a positive number if version2 and a 0 if the version ordering can't be successfully be determined.

StructureDefinition.name
Element Id StructureDefinition.name
Definition

A natural language name identifying the structure definition. This name should be usable as an identifier for the module by machine processing applications such as code generation.

Short Display Name for this structure definition (computer friendly) Cardinality Control 1..1
Type string
Requirements

Support human navigation and code generation.

Summary true
Comments

The name is not expected to be globally unique. The name should be a simple alphanumeric type name to ensure that it is machine-processing friendly.Some Examples:

  • O2SatObservation
  • PresentationReport
  • Immunization2
  • AcmeAdmissionRecordOld.
Invariants
Affect this element
cnl-0 inv-0 Warning Name should be usable as an identifier for the module by machine processing applications such as code generation name.exists() implies name.matches('^[A-Z]([A-Za-z0-9_]){1,254}$') name.matches('[A-Z]([A-Za-z0-9_]){0,254}')
StructureDefinition.title
Element Id StructureDefinition.title
Definition

A short, descriptive, user-friendly title for the structure definition.

Short Display Name for this structure definition (human friendly) Cardinality Control 0..1
Type string
Summary true
Comments

This name does not need to be machine-processing friendly and may contain punctuation, white-space, etc.Applications don't have to use this name but can always fall back to it. The title also corresponds to the label for the root element.

StructureDefinition.status
Element Id StructureDefinition.status
Definition

The status of this structure definition. Enables tracking the life-cycle of the content.

Short Display draft | active | retired | unknown Cardinality Control 1..1
Terminology Binding PublicationStatus ( Required )
Type code
Is Modifier true (Reason: This is labeled as "Is Modifier" because applications should not use a retired {{title}} without due consideration)
Summary true
Comments

Allows filtering of structure definitions that are appropriate for use versus not.

See guidance around (not) making local changes to elements here .
StructureDefinition.experimental
Element Id StructureDefinition.experimental
Definition

A Boolean value to indicate that this structure definition is authored for testing purposes (or education/evaluation/marketing) and is not intended to be used for genuine usage.

Short Display For testing purposes, not real usage Cardinality Control 0..1
Type boolean
Meaning if Missing If absent, this resource is treated as though it is not experimental. Requirements

Enables experimental content to be developed following the same lifecycle that would be used for a production-level structure definition.

Summary true
Comments

Allows filtering of structure definitions that are appropriate for use versus not.

StructureDefinition.date
Element Id StructureDefinition.date
Definition

The date (and optionally time) when the structure definition was last significantly changed. 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 structure definition changes.

Short Display Date last changed Cardinality Control 0..1
Type dateTime
Alternate Names Revision Date
Summary true
Comments

The date is often not tracked until the resource is published, but may be present on draft content. Note that this is not the same as the resource last-modified-date, since the resource may be a secondary representation of the structure definition. Additional specific dates may be added as extensions or be found by consulting Provenances associated with past versions of the resource.

See guidance around (not) making local changes to elements here .
StructureDefinition.publisher
Element Id StructureDefinition.publisher
Definition

The name of the organization or individual responsible for the release and ongoing maintenance of that published the structure definition.

Short Display Name of the publisher/steward (organization or individual) Cardinality Control 0..1
Type string
Requirements

Helps establish the "authority/credibility" of the structure definition. May also allow for contact.

Summary true
Comments

Usually an organization but may be an individual. The publisher (or steward) of the structure definition is the organization or individual primarily responsible for the maintenance and upkeep of the structure definition. This is not necessarily the same individual or organization that developed and initially authored the content. The publisher is the primary point of contact for questions or issues with the structure definition. This item SHOULD be populated unless the information is available from context.

StructureDefinition.contact
Element Id StructureDefinition.contact
Definition

Contact details to assist a user in finding and communicating with the publisher.

Short Display Contact details for the publisher Cardinality Control 0..*
Type ContactDetail
Summary true
Comments

May be a web site, an email address, a telephone number, etc.

See guidance around (not) making local changes to elements here .
StructureDefinition.description
Element Id StructureDefinition.description
Definition

A free text natural language description of the structure definition from a consumer's perspective.

Short Display Natural language description of the structure definition Cardinality Control 0..1
Type markdown
Summary false Comments

This description can be used to capture details such as why the structure definition was built, comments about misuse, instructions for clinical use and interpretation, literature references, examples from the paper world, etc. It is not a rendering of the structure definition as conveyed in the 'text' field of the resource itself. This item SHOULD be populated unless the information is available from context (e.g. the language of the structure definition is presumed to be the predominant language in the place the structure definition was created).

StructureDefinition.useContext
Element Id StructureDefinition.useContext
Definition

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 terms may be used to assist with indexing and searching for appropriate structure definition instances.

Short Display The context that the content is intended to support Cardinality Control 0..*
Type UsageContext
Requirements

Assist in searching for appropriate content.

Summary true
Comments

When multiple useContexts are specified, there is no expectation that all or any of the contexts apply.

StructureDefinition.jurisdiction
Element Id StructureDefinition.jurisdiction
Definition

A legal or geographic region in which the structure definition is intended to be used.

Short Display Intended jurisdiction for structure definition (if applicable) Cardinality Control 0..*
Terminology Binding Jurisdiction ValueSet ( Extensible )
Type CodeableConcept
Summary true
Comments

It may be possible for the structure definition to be used in jurisdictions other than those for which it was originally designed or intended.

DEPRECATION NOTE: For consistency, implementations are encouraged to migrate to using the new 'jurisdiction' code in the useContext element. (I.e. useContext.code indicating http://terminology.hl7.org/CodeSystem/usage-context-type#jurisdiction and useContext.valueCodeableConcept indicating the jurisdiction.)
StructureDefinition.purpose
Element Id StructureDefinition.purpose
Definition

Explanation of why this structure definition is needed and why it has been designed as it has.

Short Display Why this structure definition is defined Cardinality Control 0..1
Type markdown
Summary false Comments

This element does not describe the usage of the structure definition. Instead, it provides traceability of ''why'' the resource is either needed or ''why'' it is defined as it is. This may be used to point to source materials or specifications that drove the structure of this structure definition.

StructureDefinition.copyright
Element Id StructureDefinition.copyright
Definition

A copyright statement relating to the structure definition and/or its contents. Copyright statements are generally legal restrictions on the use and publishing of the structure definition. The short copyright declaration (e.g. (c) '2015+ xyz organization' should be sent in the copyrightLabel element.

Short Display Use and/or publishing restrictions Cardinality Control 0..1
Type markdown
Requirements

Consumers must be able to determine any legal restrictions on the use of the structure definition and/or its content.

Alternate Names License; Restrictions
StructureDefinition.keyword
Element Id StructureDefinition.keyword
Definition

(DEPRECATED) A set of key words or terms from external terminologies that may be used to assist with indexing and searching of templates nby describing the use of this structure definition, or the content it describes.

Short Display Assist with indexing and finding Cardinality Control 0..*
Terminology Binding Structure Definition Use Codes / Keywords ( Extensible )
Type Coding
Requirements

Assist in searching for appropriate StructureDefinitions.

Summary true
StructureDefinition.fhirVersion
Element Id StructureDefinition.fhirVersion
Definition

The version of the FHIR specification on which this StructureDefinition is based - this is the formal version of the specification, without the revision number, e.g. [publication].[major].[minor], which is 4.6.0. 3.5.0. for this version.

Short Display FHIR Version this StructureDefinition targets Cardinality Control 0..1
Terminology Binding FHIRVersion FHIRVersions ( Required )
Type code id
Summary true
Comments

A StructureDefinition does not need to specify the target it applies to as StructureDefinitions will often be valid across multiple versions of FHIR. FHIR tooling can determine whether a StructureDefinition is consistent with a particular StructureDefinition if desired.

StructureDefinition.mapping
Element Id StructureDefinition.mapping
Definition

An external specification that the content is mapped to.

Short Display External specification that the content is mapped to Cardinality Control 0..*
Summary false Invariants
Defined on this element
sdf-2 Rule Must have at least a name or a uri (or both) name.exists() or uri.exists()
StructureDefinition.mapping.identity
Element Id StructureDefinition.mapping.identity
Definition

An Internal id that is used to identify this mapping set when specific mappings are made.

Short Display Internal id when this mapping is used Cardinality Control 1..1
Type id
Summary false Comments

The specification is described once, with general comments, and then specific mappings are made that reference this declaration.

StructureDefinition.mapping.uri
Element Id StructureDefinition.mapping.uri
Definition

An absolute URI that identifies the specification that this mapping is expressed to.

Short Display Identifies what this mapping refers to Cardinality Control 0..1
Type uri
Summary false Comments

A formal identity for the specification being mapped to helps with identifying maps consistently.

Invariants
Affect this element
sdf-2 Rule Must have at least a name or a uri (or both) name.exists() or uri.exists()
StructureDefinition.mapping.name
Element Id StructureDefinition.mapping.name
Definition

A name for the specification that is being mapped to.

Short Display Names what this mapping refers to Cardinality Control 0..1
Type string
Summary false Invariants
Affect this element
sdf-2 Rule Must have at least a name or a uri (or both) name.exists() or uri.exists()
StructureDefinition.mapping.comment
Element Id StructureDefinition.mapping.comment
Definition

Comments about this mapping, including version notes, issues, scope limitations, and other important notes for usage.

Short Display Versions, Issues, Scope limitations etc Cardinality Control 0..1
Type string
StructureDefinition.kind
Element Id StructureDefinition.kind
Definition

Defines the kind of structure that this definition is describing.

Short Display primitive-type | complex-type | resource | logical Cardinality Control 1..1
Terminology Binding Structure Definition Kind StructureDefinitionKind ( Required )
Type code
Summary true
StructureDefinition.abstract
Element Id StructureDefinition.abstract
Definition

Whether structure this definition describes is abstract or not - that is, whether the structure is not intended to be instantiated. For Resources and Data types, abstract types will never be exchanged between systems.

Short Display Whether the structure is abstract Cardinality Control 1..1
Type boolean
Summary true
Comments

Abstract Resources cannot be instantiated - a concrete sub-type must be used. Abstract datatypes and extensions cannot be used in an instance. For logical models, the exact implication of "abstract" will rest with the author, depending how the logical model is used. Flagging a constraint structure as abstract conveys design intent but makes no difference to how the structure definition is handled. Note that inline declared elements that are given the type "Element" in the StructureDefinition, but have children described, are anonymous concrete types that specialize Element.

StructureDefinition.context
Element Id StructureDefinition.context
Definition

Identifies the types of resource or data type elements to which the extension can be applied. For more guidance on using the 'context' element, see the defining extensions page .

Short Display If an extension, where it can be used in instances Cardinality Control 0..*
Summary true
Invariants
Affect this element
sdf-5 Rule If the structure defines an extension then the structure must have context information type != 'Extension' or derivation = 'specialization' or (context.exists())
StructureDefinition.context.type
Element Id StructureDefinition.context.type
Definition

Defines how to interpret the expression that defines what the context of the extension is.

Short Display fhirpath | element | extension Cardinality Control 1..1
Terminology Binding Extension Context Type ExtensionContextType ( Required )
Type code
Summary true
StructureDefinition.context.expression
Element Id StructureDefinition.context.expression
Definition

An expression that defines where an extension can be used in resources.

Short Display Where the extension can be used in instances Cardinality Control 1..1
Type string
Summary true
StructureDefinition.contextInvariant
Element Id StructureDefinition.contextInvariant
Definition

A set of rules as FHIRPath Invariants about when the extension can be used (e.g. co-occurrence variants for the extension). All the rules must be true.

Short Display FHIRPath invariants - when the extension can be used Cardinality Control 0..*
Type string
Summary true
Comments

The rules are only evaluated when the extension is present. When evaluating the invariant, the FHIRPath focus is the element that holds the extension, and %extension refers to the extension itself.

Invariants
Affect this element
sdf-18 Rule Context Invariants can only be used for extensions contextInvariant.exists() implies type = 'Extension'
StructureDefinition.type
Element Id StructureDefinition.type
Definition

The type this structure describes. If the derivation kind is 'specialization' then this is the master definition for a type, and there is always one of these (a data type, an extension, a resource, including abstract ones). Otherwise the structure definition is a constraint on the stated type (and in this case, the type cannot be an abstract type). References are URLs that are relative to http://hl7.org/fhir/StructureDefinition e.g. "string" is a reference to http://hl7.org/fhir/StructureDefinition/string. Absolute URLs are only allowed in logical models, where they are required. models.

Short Display Type defined or constrained by this structure Cardinality Control 1..1
Terminology Binding All FHIR Types FHIRDefinedType ( Extensible )
Type uri
Summary true
Comments

Note that in the case of constraints, the type could be determined by chasing through the baseDefinition references until a type defining concrete structure (derivation = specialization) is reached, or by looking at the path of the first element in the snapshot - if present - but providing the type directly makes for simpler tooling and indexing.

The type must match the elements defined in the differential and the snapshot. For all FHIR defined types, the path name of the element will start with the type name. For logical models, where the type SHALL be is a fully specified URL, the type name SHOULD start with the final path segment tail of the type URL where required. E.g. If the type was "http://example.org/fhir/MyLogicalModelType", the type name should start with 'MyLogicalModelType'.

Invariants sdf-5 Rule If the structure defines an extension then the structure must have context information type != 'Extension' or derivation = 'specialization' or (context.exists()) sdf-8 Rule All snapshot elements must start with the StructureDefinition's specified type for non-logical models, or with the same type name for logical models (%resource.kind = 'logical' or element.first().path = %resource.type) and element.tail().all(path.startsWith(%resource.snapshot.element.first().path&'.')) sdf-8a Rule In any differential, all the elements must start with the StructureDefinition's specified type for non-logical models, or with the same type name for logical models (%resource.kind = 'logical' or element.first().path.startsWith(%resource.type)) and (element.tail().empty() or element.tail().all(path.startsWith(%resource.differential.element.first().path.replaceMatches('\\..*','')&'.')))
Affect this element
sdf-18 Rule Context Invariants can only be used for extensions contextInvariant.exists() implies type = 'Extension' sdf-11 Rule If there's a type, its content must match the path name in the first element of a snapshot kind != 'logical' implies snapshot.empty() or snapshot.element.first().path = type
StructureDefinition.baseDefinition
Element Id StructureDefinition.baseDefinition
Definition

An absolute URI that is the base structure from which this type is derived, either by specialization or constraint.

Short Display Definition that this type is constrained/specialized from Cardinality Control 0..1
Type canonical ( StructureDefinition )
Hierarchy This reference is part of a strict Hierarchy
Summary true
Comments

If differential constraints are specified in this structure, they are applied to the base in a "differential" fashion. If there is no base, then the differential constraints cannot be provided (snapshot only). Differential structures are useful for the editing perspective, and snapshot structures are suitable for operational use. The FHIR Project provides a number of tools/services to populate snapshots from differential constraints. Logical Models have a base of "Base", "Element" or another logical model.

Invariants sdf-27 Rule If there's a base definition, there must be a derivation baseDefinition.exists() implies derivation.exists()
Affect this element
sdf-4 Rule If the structure is not abstract, then there SHALL be a baseDefinition abstract = true or baseDefinition.exists()
StructureDefinition.derivation
Element Id StructureDefinition.derivation
Definition

How the type relates to the baseDefinition.

Short Display specialization | constraint - How relates to base definition Cardinality Control 0..1
Terminology Binding Type Derivation Rule TypeDerivationRule ( Required )
Type code
Summary true
Comments

If the definition is a specialization, then it adds to the differential new elements and optionally additional rules to an existing concrete type, in the differential, and the snapshot includes the inherited elements and rules. elements. If the definition is a constraint, then it cannot define new elements, it can only make new rules about existing content (see Profiling Resources ).

StructureDefinition.snapshot
Element Id StructureDefinition.snapshot
Definition

A snapshot view is expressed in a standalone form that can be used and interpreted without considering the base StructureDefinition.

Short Display Snapshot view of the structure Cardinality Control 0..1
Summary false Invariants
Defined on this element
sdf-3 Rule Each element definition in a snapshot must have a formal definition and cardinalities, unless model is a logical model cardinalities %resource.kind = 'logical' or element.all(definition.exists() and min.exists() and max.exists())
sdf-8 Rule All snapshot elements must start with be in the StructureDefinition's specified type for non-logical models, or with the same type name for logical models (%resource.kind = 'logical' or element.first().path = %resource.type) and element.tail().all(path.startsWith(%resource.snapshot.element.first().path&'.')) sdf-24 Rule For CodeableReference elements, target profiles must be listed on the CodeableReference, not the CodeableReference.reference element.where(type.where(code='Reference').exists() and path.endsWith('.reference') and type.targetProfile.exists() and (path.substring(0,$this.path.length()-10) in %context.element.where(type.where(code='CodeableReference').exists()).path)).exists().not() sdf-25 Rule For CodeableReference elements, bindings must be listed on the CodeableReference, not the CodeableReference.concept element.where(type.where(code='CodeableConcept').exists() and path.endsWith('.concept') and binding.exists() %resource.type and (path.substring(0,$this.path.length()-8) in %context.element.where(type.where(code='CodeableReference').exists()).path)).exists().not() sdf-26 Guideline The root element of a profile should not have mustSupport = true $this.where(element[0].mustSupport='true').exists().not() element.tail().all(path.startsWith(%resource.type&'.')) This is (only) a best practice guideline because: It is bad practice to set the root element of a profile to 'mustSupport' as mustSupport should always be determined by the element referencing a type. The designer of a StructureDefinition cannot know all circumstances in which a type or profile might be used
sdf-8b Rule All snapshot elements must have a base definition element.all(base.exists())
Affect this element
sdf-11 Rule If there's a type, its content must match the path name in the first element of a snapshot kind != 'logical' implies snapshot.empty() or snapshot.element.first().path = type sdf-1 Rule Element paths must be unique unless the structure is a constraint derivation = 'constraint' or snapshot.element.select(path).isDistinct() sdf-6 Rule A structure must have either a differential, or a snapshot (or both) snapshot.exists() or differential.exists()
StructureDefinition.snapshot.element
Element Id StructureDefinition.snapshot.element
Definition

Captures constraints on each element within the resource.

Short Display Definition of elements in the resource (if no StructureDefinition) Cardinality Control 1..*
Type ElementDefinition
Summary false Invariants sdf-28 Rule If there are no discriminators, there must be a definition slicing.exists().not() or (slicing.discriminator.exists() or slicing.description.exists()) sdf-8b Rule All snapshot elements must have a base definition element.all(base.exists()) sdf-24 Rule For CodeableReference elements, target profiles must be listed on the CodeableReference, not the CodeableReference.reference element.where(type.where(code='Reference').exists() and path.endsWith('.reference') and type.targetProfile.exists() and (path.substring(0,$this.path.length()-10) in %context.element.where(type.where(code='CodeableReference').exists()).path)).exists().not() sdf-25 Rule For CodeableReference elements, bindings must be listed on the CodeableReference, not the CodeableReference.concept element.where(type.where(code='CodeableConcept').exists() and path.endsWith('.concept') and binding.exists() and (path.substring(0,$this.path.length()-8) in %context.element.where(type.where(code='CodeableReference').exists()).path)).exists().not() sdf-26 Guideline The root element of a profile should not have mustSupport = true $this.where(element[0].mustSupport='true').exists().not() This is (only) a best practice guideline because: It is bad practice to set the root element of a profile to 'mustSupport' as mustSupport should always be determined by the element referencing a type. The designer of a StructureDefinition cannot know all circumstances in which a type or profile might be used
Defined on this element
sdf-10 Rule provide either a binding reference or a description (or both) binding.empty() or binding.valueSet.exists() or binding.description.exists()
Affect this element
sdf-9 Rule In any snapshot or differential, no label, code or requirements on an element without a "." in the path (e.g. the first element) children().element.where(path.contains('.').not()).label.empty() and children().element.where(path.contains('.').not()).code.empty() and children().element.where(path.contains('.').not()).requirements.empty() sdf-19 Rule FHIR Specification models only use FHIR defined types url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (differential | snapshot).element.type.code.all(matches('^[a-zA-Z0-9]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$')) sdf-16 Rule All element definitions must have unique ids (snapshot) snapshot.element.all(id.exists()) and snapshot.element.id.trace('ids').isDistinct() sdf-15 Rule The first element in a snapshot has no type unless model is a logical model. kind!='logical' implies snapshot.element.first().type.empty() sdf-23 Rule No slice name on root (snapshot | differential).element.all(path.contains('.').not() implies sliceName.empty()) sdf-11 Rule If there's a type, its content must match the path name in the first element of a snapshot kind != 'logical' implies snapshot.empty() or snapshot.element.first().path = type sdf-22 Rule FHIR Specification models never have default values url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (snapshot.element.defaultValue.empty() and differential.element.defaultValue.empty()) sdf-14 Rule All element definitions must have an id snapshot.element.all(id.exists()) and differential.element.all(id.exists()) sdf-1 Rule Element paths must be unique unless the structure is a constraint derivation = 'constraint' or snapshot.element.select(path).isDistinct() sdf-8 Rule All snapshot elements must start with the StructureDefinition's specified type for non-logical models, or with the same type name for logical models (%resource.kind = 'logical' or element.first().path = %resource.type) and element.tail().all(path.startsWith(%resource.snapshot.element.first().path&'.')) sdf-3 Rule Each element definition in a snapshot must have a formal definition and cardinalities, unless model is a logical model cardinalities %resource.kind = 'logical' or element.all(definition.exists() and min.exists() and max.exists())
StructureDefinition.differential
Element Id StructureDefinition.differential
Definition

A differential view is expressed relative to the base StructureDefinition - a statement of differences that it applies.

Short Display Differential view of the structure Cardinality Control 0..1
Summary false Invariants
Defined on this element
sdf-20 Rule No slicing on the root element element.where(path.contains('.').not()).slicing.empty()
sdf-8a Rule In any differential, all the elements must start with be in the StructureDefinition's specified type for non-logical models, or with the same type name for logical models (%resource.kind = 'logical' or element.first().path.startsWith(%resource.type)) element.first().path.startsWith(%resource.type) and (element.tail().empty() (element.tail().not() or element.tail().all(path.startsWith(%resource.differential.element.first().path.replaceMatches('\\..*','')&'.'))) element.tail().all(path.startsWith(%resource.type&'.')))
Affect this element
sdf-6 Rule A structure must have either a differential, or a snapshot (or both) snapshot.exists() or differential.exists()
StructureDefinition.differential.element
Element Id StructureDefinition.differential.element
Definition

Captures constraints on each element within the resource.

Short Display Definition of elements in the resource (if no StructureDefinition) Cardinality Control 1..*
Type ElementDefinition