---
type: "datatype"
title: "Meta"
datatype: "Meta"
---
# Meta

- [Datatypes](/datatypes)
- [Definitions](/datatypes-definitions#Meta)
- [Examples](/datatypes-examples#Meta)
- [Mappings](/datatypes-mappings#Meta)
- [Profiles](/datatypes-profiles#Meta)

## Elements

- **[Meta.versionId](/datatypes-definitions#Meta.versionId)** [0..1]: [id](/id) The version specific identifier, as it appears in the version portion of the URL. This value changes when the resource is created, updated, or deleted
- **[Meta.lastUpdated](/datatypes-definitions#Meta.lastUpdated)** [0..1]: [instant](/instant) When the resource last changed - e.g. when the version changed
- **[Meta.source](/datatypes-definitions#Meta.source)** [0..1]: [uri](/uri) A uri that identifies the data source of the resource. This provides a minimal amount of [[[Provenance]]] information that can be used to track or differentiate the source of information in the resource. The source may identify another server, document, message, database, etc. It can also refer to portions of a structure, such as a section, segment, row, etc.
- **[Meta.profile](/datatypes-definitions#Meta.profile)** [0..*]: canonical(StructureDefinition) A list of profiles (references to [[[StructureDefinition]]] resources) that this resource claims to conform to. The URL is a reference to [[[StructureDefinition.url]]]
- **[Meta.security](/datatypes-definitions#Meta.security)** [0..*]: [Coding](/Coding) Security labels applied to this resource. These tags connect specific resources to the overall security policy and infrastructure
- **[Meta.tag](/datatypes-definitions#Meta.tag)** [0..*]: [Coding](/Coding) Tags applied to this resource. Tags are intended to be used to identify and relate resources to process and workflow, and applications are not required to consider the tags when interpreting the meaning of a resource

## Bindings

- **Meta.security**: `SecurityLabels`
- **Meta.tag**: `Tags` | strength: value set | reference: valueset-common-tags

## Comments

- **Meta.versionId**: The server assigns this value, and ignores what the client specifies, except in the case that the server is imposing version integrity on updates/deletes
- **Meta.lastUpdated**: This element is generally omitted in instances submitted in a PUT or POST. Instead, it might be populated by the server when data is received or assigned when crafting the instance when constructing a response. The server / resource manager sets this value; what a client provides can be irrelevant. This is equivalent to the HTTP Last-Modified and SHOULD have the same value on a read interaction.

Note that there are scenarios where changes in a resource do not trigger a change in the `lastUpdated` value and there are scenarios where changes in `lastUpdated` are made even though there are no visible changes in the resource. Unless specified otherwise, this element MAY be out of sync with changes in either direction. For example:



* If a system uses mapping tables to generate resources (e.g., a facade server), updates to those tables might not be reflected in `lastUpdated` but do result in a difference of retrieved resource content.

* If a system generates resources from internal data (e.g., a facade server), the system's internal `lastUpdated` value might be changed due to changes that are not visible on FHIR resources (e.g., extended data has been changed).

* If a system updates an element that a particular client does not have access to (e.g., prevented by privacy rules), the `lastUpdated` value might be changed even though there are no visible changes in resource content.



Note to server implementers: updating `lastUpdated` too frequently is generally preferred over missing updates. It is better for client to retrieve records too frequently rather than missing updates.
- **Meta.source**: The exact use of the source (and the possible implied Provenance.entity.role and agent.role) is left to implementer discretion. Only one nominated source is allowed; for additional provenance details, a full Provenance resource should be used. The source may correspond to Provenance.entity.what[x] or Provenance.agent.who[x], though it may be a more general or abstract reference. 

This element can be used to indicate where the current master source of a resource that has a canonical URL if the resource is no longer hosted at the canonical URL
- **Meta.profile**: It is up to the server and/or other infrastructure of policy to determine whether/how these claims are verified and/or updated over time. The list of profile URLs is a set
- **Meta.security**: The security labels can be updated without changing the stated version of the resource. The list of security labels is a set. Uniqueness is based the system/code, and version and display are ignored
- **Meta.tag**: The tags can be updated without changing the stated version of the resource. The list of tags is a set. Uniqueness is based the system/code, and version and display are ignored