Complex
Primitive
ActivityDefinition
CapabilityStatement
CodeSystem
Composition
ConceptMap
Encounter
Library
List
Measure
MessageHeader
Observation
Patient
PlanDefinition
Questionnaire
Resource
ServiceDefinition
StructureDefinition
StructureMap
ValueSet
default
Base StructureDefinition for Attachment Type
Attachment
Path
Attachment
Id
Attachment
Cardinality
0 - *
Definition
For referring to data content defined in other formats.
Comment
When providing a summary view (for example with Observation.value[x]) Attachment should be represented with a brief display text such as "Attachment".
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
att-1 [error]
It the Attachment has data, it SHALL have a contentType
Condition
ele-1
Path
Attachment.contentType
Id
Attachment.contentType
Type
Cardinality
0 - 1
Definition
Identifies the type of the data in the attachment and allows a method to be chosen to interpret or render the data. Includes mime type parameters such as charset where appropriate.
Comment
Requirements
Processors of the data need to be able to know how to interpret the data.
Path
Attachment.data
Id
Attachment.data
Type
Cardinality
0 - 1
Definition
The actual data of the attachment - a sequence of bytes. In XML, represented using base64.
Comment
The base64-encoded data SHALL be expressed in the same character set as the base resource XML or JSON.
Requirements
The data needs to able to be transmitted inline.
Path
Attachment.url
Id
Attachment.url
Type
Cardinality
0 - 1
Definition
An alternative location where the data can be accessed.
Comment
If both data and url are provided, the url SHALL point to the same content as the data contains. Urls may be relative references or may reference transient locations such as a wrapping envelope using cid: though this has ramifications for using signatures. Relative URLs are interpreted relative to the service url, like a resource reference, rather than relative to the resource itself. If a URL is provided, it SHALL resolve to actual data.
Requirements
The data needs to be transmitted by reference.
Path
Attachment.size
Id
Attachment.size
Type
Cardinality
0 - 1
Definition
The number of bytes of data that make up this attachment (before base64 encoding, if that is done).
Comment
The number of bytes is redundant if the data is provided as a base64binary, but is useful if the data is provided as a url reference.
Requirements
Representing the size allows applications to determine whether they should fetch the content automatically in advance, or refuse to fetch it at all.
Path
Attachment.hash
Id
Attachment.hash
Type
Cardinality
0 - 1
Definition
The calculated hash of the data using SHA-1. Represented using base64.
Comment
The hash is calculated on the data prior to base64 encoding, if the data is based64 encoded.
Requirements
Included so that applications can verify that the contents of a location have not changed and so that a signature of the content can implicitly sign the content of an image without having to include the data in the instance or reference the url in the signature.
Path
Attachment.title
Id
Attachment.title
Type
Cardinality
0 - 1
Definition
A label or set of text to display in place of the data.
Comment
Requirements
Applications need a label to display to a human user in place of the actual data if the data cannot be rendered or perceived by the viewer.
Path
Attachment.creation
Id
Attachment.creation
Type
Cardinality
0 - 1
Definition
The date that the attachment was first created.
Comment
Requirements
This is often tracked as an integrity issue for use of the attachment.