description: 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](versions.html#extensions).
package_name: hl7.fhir.uv.extensions
derivation: constraint
name: Datatype
type: Extension
elements:
  extension: {index: 0}
  url:
    pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/_datatype'}
    index: 1
  value:
    choices: [valueString]
    index: 3
  valueString: {type: string, choiceOf: value, index: 4}
package_version: 5.1.0-cibuild
extensions: {}
class: extension
kind: complex-type
url: http://hl7.org/fhir/StructureDefinition/_datatype
base: http://hl7.org/fhir/StructureDefinition/Extension
version: 5.1.0-cibuild
required: [valueString, value]