FHIR Release 3 (STU) Current Build
FHIR Infrastructure Work Group Maturity Level : 5 Normative Ballot Standards Status : Trial Use Normative
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Extension
Standards Status This element has a standards status of "Normative"
Definition

Optional Extension Element - found in all resources.

Control Cardinality 1..1 0..*
Type Element
Requirements

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

Invariants
Defined on this element
ext-1 : Rule 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')])) value.exists()
Extension.url
Definition

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

Control Cardinality 1..1
Type uri
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 must be a resource or one of a constrained set of the data types (see Extensibility in the spec for a list).

Control Cardinality 0..1
Type *
[x] Note See Choice of Data Types for further information about how to use [x]