R4 Ballot #1 (Mixed Normative/Trial use)

This page is part of the FHIR Specification (v3.3.0: R4 Ballot 2). The current 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

2.5.3 Extension - Detailed Descriptions

FHIR Infrastructure Work GroupMaturity Level: 5Ballot Status: Normative

Normative Candidate Note: This page is candidate normative content for R4 in the Infrastructure Package. Once normative, it will lose it's Maturity Level, and breaking changes will no longer be made.

Extension
Standards StatusThis element has a standards status of "Normative" which is different to the status of the whole resource
Definition

Optional Extension Element - found in all resources.

Control1..1
Requirements

The ability to add extensions in a structured way is what keeps FHIR resources simple.

InvariantsDefined on this element
ext-1: Must have either extensions or value[x], not both (expression : extension.exists() != value.exists(), xpath: exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')]))
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.

Extension.value[x]
Definition

Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

Control0..1
Type*
[x] NoteSee Choice of Data Types for further information about how to use [x]