Element-extensions - FHIR v5.0.0-ballot

Release 5 Ballot

This page is part of the FHIR Specification (v5.0.0-ballot: FHIR R5 Ballot Preview). 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

Element-definition Extensions for use by FHIR Implementers

FHIR Infrastructure Work Group

Maturity Level: N/A

Standards Status: Informative

Scope and Usage

This profile defines extensions that can be used to describe the additional characteristics that must be held by a data element.

Data elements can be defined in several places. The extensions defined within this profile may apply to most or all of these:

StructureDefinition.*.element - defining the characteristics of the data elements and extensions when used according to the profile
Questionnaire.item - defining the characteristics of permitted answers

Note: Implementations are not required to reject invalid data. However, transmitting data that violates one of these extensions would be considered invalid against the resource that declared the extension.

The extensions provided here fall into several categories:

Length-related (govern allowed length of an element): minLength, maxLength
Format (govern the appearance of string and string-like simple data types): entryFormat
Numeric/date (govern the allowed range of numeric, date or time data types): minValue, maxValue, maxDecimalPlaces
Attachment-related (govern allowed attachments): mimeType, maxSize

Content

Extensions:
minLength	minLength : The minimum number of characters that must be present in the simple data type to be considered a "valid" instance.
entryFormat	entryFormat : Additional instructions for the user to guide their input (i.e. a human readable version of a regular expression like "nnn-nnn-nnn"). In most UIs this is the placeholder (or 'ghost') text placed directly inside the edit controls and that disappear when the control gets the focus.
minValue	minValue : The inclusive lower bound on the range of allowed values for the data element.
maxValue	maxValue : The inclusive upper bound on the range of allowed values for the data element.
maxDecimalPlaces	maxDecimalPlaces : Identifies the maximum number of decimal places that may be specified for the data element.
mimeType	mimeType : Identifies the kind(s) of attachment allowed to be sent for an element.
maxSize	maxSize : For attachment answers, indicates the maximum size in bytes an attachment can be.
alternate-reference	alternate-reference : Used when the target of the reference has a type that is not allowed by the definition of the element. In general, this should only arise when wrangling between versions using cross-version extensions.
alternate-canonical	alternate-canonical : Used when the target of the reference has a type that is not allowed by the definition of the element. In general, this should only arise when wrangling between versions using cross-version extensions.
_datatype	_datatype : Used when the actual type is not allowed by the definition of the element. In general, this should only arise when wrangling between versions using cross-version extensions - see Cross Version Extensions.