A formal computable definition of an operation (on the RESTful interface) or a named query (using the search interaction).

An absolute URI that is used to identify this operation definition when it is referenced in a specification, model, design or an instance; also called its canonical identifier. This SHOULD be globally unique and SHOULD be a literal address at which an authoritative instance of this operation definition is (or will be) published. This URL can be the target of a canonical reference. It SHALL remain the same when the operation definition is stored on different servers.

Allows the operation definition to be referenced by a single globally unique identifier.

Can be a urn:uuid: or a urn:oid: but real http: addresses are preferred. Multiple instances may share the same URL if they have a distinct version.

The determination of when to create a new version of a resource (same url, new version) vs. defining a new artifact is up to the author. Considerations for making this decision are found in Technical and Business Versions.

In some cases, the resource can no longer be found at the stated url, but the url itself cannot change. Implementations can use the meta.source element to indicate where the current master source of the resource can be found.

The identifier that is used to identify this version of the operation definition when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the operation definition author and is not expected to be globally unique. For example, it might be a timestamp (e.g. yyyymmdd) if a managed version is not available. There is also no expectation that versions can be placed in a lexicographical sequence.

There may be different operation definition instances that have the same identifier but different versions. The version can be appended to the url in a reference to allow a reference to a particular business version of the operation definition with the format [url]|[version]. The version SHOULD NOT contain a '#' - see Business Version.

Indicates the mechanism used to compare versions to determine which is more current.

If set as a string, this is a FHIRPath expression that has two additional context variables passed in - %version1 and %version2 and will return a negative number if version1 is newer, a positive number if version2 and a 0 if the version ordering can't be successfully be determined.

A natural language name identifying the operation definition. This name should be usable as an identifier for the module by machine processing applications such as code generation.

Support human navigation and code generation.

The name is not expected to be globally unique. The name should be a simple alphanumeric type name to ensure that it is machine-processing friendly.

A short, descriptive, user-friendly title for the operation definition.

This name does not need to be machine-processing friendly and may contain punctuation, white-space, etc.

The status of this operation definition. Enables tracking the life-cycle of the content.

Allows filtering of operation definitions that are appropriate for use versus not.

Whether this is an operation or a named query.

Named queries are invoked differently, and have different capabilities.

A Boolean value to indicate that this operation definition is authored for testing purposes (or education/evaluation/marketing) and is not intended to be used for genuine usage.

Enables experimental content to be developed following the same lifecycle that would be used for a production-level operation definition.

Allows filtering of operation definitions that are appropriate for use versus not.

The date (and optionally time) when the operation definition was last significantly changed. The date must change when the business version changes and it must change if the status code changes. In addition, it should change when the substantive content of the operation definition changes.

The date is often not tracked until the resource is published, but may be present on draft content. Note that this is not the same as the resource last-modified-date, since the resource may be a secondary representation of the operation definition. Additional specific dates may be added as extensions or be found by consulting Provenances associated with past versions of the resource.

The name of the organization or individual responsible for the release and ongoing maintenance of the operation definition.

Helps establish the "authority/credibility" of the operation definition. May also allow for contact.

Usually an organization but may be an individual. The publisher (or steward) of the operation definition is the organization or individual primarily responsible for the maintenance and upkeep of the operation definition. This is not necessarily the same individual or organization that developed and initially authored the content. The publisher is the primary point of contact for questions or issues with the operation definition. This item SHOULD be populated unless the information is available from context.

Contact details to assist a user in finding and communicating with the publisher.

May be a web site, an email address, a telephone number, etc.

A free text natural language description of the operation definition from a consumer's perspective.

This description can be used to capture details such as comments about misuse, instructions for clinical use and interpretation, literature references, examples from the paper world, etc. It is not a rendering of the operation definition as conveyed in the 'text' field of the resource itself. This item SHOULD be populated unless the information is available from context (e.g. the language of the operation definition is presumed to be the predominant language in the place the operation definition was created).

The content was developed with a focus and intent of supporting the contexts that are listed. These contexts may be general categories (gender, age, ...) or may be references to specific programs (insurance plans, studies, ...) and may be used to assist with indexing and searching for appropriate operation definition instances.

Assist in searching for appropriate content.

When multiple useContexts are specified, there is no expectation that all or any of the contexts apply.

A legal or geographic region in which the operation definition is intended to be used.

It may be possible for the operation definition to be used in jurisdictions other than those for which it was originally designed or intended.

Explanation of why this operation definition is needed and why it has been designed as it has.

This element does not describe the usage of the operation definition. Instead, it provides traceability of ''why'' the resource is either needed or ''why'' it is defined as it is. This may be used to point to source materials or specifications that drove the structure of this operation definition.

A copyright statement relating to the OperationDefinition and/or its contents. Copyright statements are generally legal restrictions on the use and publishing of the OperationDefinition.

Consumers must be able to determine any legal restrictions on the use of the OperationDefinition and/or its content.

...

A short string (<50 characters), suitable for inclusion in a page footer that identifies the copyright holder, effective period, and optionally whether rights are resctricted. (e.g. 'All rights reserved', 'Some rights reserved').

Defines the content expected to be rendered in all representations of the artifact.

The (c) symbol should NOT be included in this string. It will be added by software when rendering the notation. Full details about licensing, restrictions, warrantees, etc. goes in the more general 'copyright' element.

Whether the operation affects state. Side effects such as producing audit trail entries do not count as 'affecting state'.

What http methods can be used for the operation depends on the .affectsState value and whether the input parameters are primitive or complex:

1. Servers SHALL support POST method for all operations.

2. Servers SHALL support the GET method when the operation has affectsState = false and all required parameters for the operation are primitive.

The label that is recommended to be used in the URL for this operation. In some cases, servers may need to use a different CapabilityStatement operation.name to differentiate between multiple SearchParameters that happen to have the same code.

For maximum compatibility, use only lowercase ASCII characters. Note that HL7 will never define multiple operations with the same code. See Naming Rules & Guidelines for the internal HL7 rules around codes, which are useful additional advice for all implementers

Additional information about how to use this operation or named query.

Indicates that this operation definition is a constraining profile on the base.

A constrained profile can make optional parameters required or not used, introduce new parameters (required or optional), and clarify documentation.

The types on which this operation can be executed.

If the type is an abstract resource ("Resource" or "DomainResource") then the operation can be invoked on any concrete specialization.

Indicates whether this operation or named query can be invoked at the system level (e.g. without needing to choose a resource type for the context).

Indicates whether this operation or named query can be invoked at the resource type level for any given resource type level (e.g. without needing to choose a specific resource id for the context).

Indicates whether this operation can be invoked on a particular instance of one of the given types.

Additional validation information for the in parameters - a single profile that covers all the parameters. The profile is a constraint on the parameters resource as a whole.

If present the profile shall not conflict with what is specified in the parameters in the operation definition (max/min etc.), though it may provide additional constraints. The constraints expressed in the profile apply whether the operation is invoked by a POST wih parameters or not.

Additional validation information for the out parameters - a single profile that covers all the parameters. The profile is a constraint on the parameters resource.

If present the profile shall not conflict with what is specified in the parameters in the operation definition (max/min etc.), though it may provide additional constraints. The constraints expressed in the profile apply whether the operation is invoked by a POST wih parameters or not.

The parameters for the operation/query.

Query Definitions only have one output parameter, named "result". This might not be described, but can be to allow a profile to be defined.

The name of used to identify the parameter.

This name must be a token (start with a letter in a..z, and only contain letters, numerals, and underscore. Note that for search parameters (type = string, with a search type), the name may be altered by the search modifiers.

Whether this is an input or an output parameter.

If a parameter name is used for both an input and an output parameter, the parameter should be defined twice.

If present, indicates that the parameter applies when the operation is being invoked at the specified level.

The minimum number of times this parameter SHALL appear in the request or response.

The maximum number of times this element is permitted to appear in the request or response.

Describes the meaning or use of this parameter.

The type for this parameter.

if there is no stated parameter, then the parameter is a multi-part parameter type and must have at least one part defined.

Support for polymorphic types. If the parameter type is abstract, this element lists allowed sub-types for the parameter.

In previous versions of FHIR, there was an extension for this: http://hl7.org/fhir/StructureDefinition/operationdefinition-allowed-type

Used when the type is "Reference" or "canonical", and identifies a profile structure or implementation Guide that applies to the target of the reference this parameter refers to. If any profiles are specified, then the content must conform to at least one of them. The URL can be a local reference - to a contained StructureDefinition, or a reference to another StructureDefinition or Implementation Guide by a canonical URL. When an implementation guide is specified, the target resource SHALL conform to at least one profile defined in the implementation guide.

Often, these profiles are the base definitions from the spec (e.g. http://hl7.org/fhir/StructureDefinition/Patient).

How the parameter is understood if/when it used as search parameter. This is only used if the parameter is a string.

Parameters that are search parameter usually - but not always - are also defined for use with general searches, and function in the operation to filter the set of resources in scope for the operation just like the do when searching. The searchType describes how the server processes the value. For an example, see the Evaluate Measure Operation

Binds to a value set if this parameter is coded (code, Coding, CodeableConcept).

Indicates the degree of conformance expectations associated with this binding - that is, the degree to which the provided value set must be adhered to in the instances.

For further discussion, see Using Terminologies.

Points to the value set or external definition (e.g. implicit value set) that identifies the set of codes to be used.

For value sets with a referenceResource, the display can contain the value set description. The reference may be version-specific or not.

Identifies other resource parameters within the operation invocation that are expected to resolve to this resource.

Resolution applies if the referenced parameter exists.

The name of the parameter or dot-separated path of parameter names pointing to the resource parameter that is expected to contain a reference to this resource.

The id of the element in the referencing resource that is expected to resolve to this resource.

The parts of a nested Parameter.

Query Definitions only have one output parameter, named "result". This might not be described, but can be to allow a profile to be defined.

Defines an appropriate combination of parameters to use when invoking this operation, to help code generators when generating overloaded parameter sets for this operation.

The combinations are suggestions as to which sets of parameters to use together, but the combinations are not intended to be authoritative.

Name of parameter to include in overload.

Comments to go on overload.