Structured Data Capture
3.0.0 - STU 3 International flag

This page is part of the Structured Data Capture FHIR IG (v3.0.0: STU 3) based on FHIR R4. This is the current published version in its permanent home (it will always be available at this URL). For a full list of available versions, see the Directory of published versions

Extension: CandidateExpressionExtension - Detailed Descriptions

Page standards status: Trial-use Maturity Level: 3

Definitions for the sdc-questionnaire-candidateExpression extension.

1. Extension
Definition

A FHIRPath or CQL expression, or FHIR Query that resolves to a list of candidate answers for the question item or that establishes context for a group item. The user may select from among the candidates to choose answers for the question.

Control0..1 This element is affected by the following invariants: ele-1
Comments

The results of the expression must correspond to the item type of the question the element appears on or must correspond to a resource, backbone element or complex data type for a group item. Resources are considered a match for the Reference item type. Quantity can be a match for decimal and integer items so long as a questionnaire-unit extension is present.

InvariantsDefined on this element
ele-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.

Control0..1
Typestring
3. 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 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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

InvariantsDefined on this element
ele-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 are unordered and Open, and can be differentiated using the following discriminators:
  • value @ url
4. Extension.url
Definition

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

Control1..1
Typeuri
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.

Fixed Valuehttp://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-candidateExpression
5. Extension.value[x]
Definition

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

Control0..1
TypeExpression
[x] NoteSee Choice of Data Types for further information about how to use [x]
InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (: hasValue() or (children().count() > id.count()))