description: An extension to carry an indicator for the event date of a data change at the source system package_name: fhir.r4.wales.stu1 derivation: constraint name: ExtensionDataStandardsWalesCdrSourceTimestamp type: Extension elements: url: pattern: {type: uri, value: 'https://fhir.nhs.wales/StructureDefinition/Extension-DataStandardsWales-CDRSourceTimestamp'} type: uri index: 0 value: choices: [valueDateTime] index: 2 valueDateTime: {type: dateTime, choiceOf: value, index: 3} package_version: 1.1.0 class: extension kind: complex-type url: https://fhir.nhs.wales/StructureDefinition/Extension-DataStandardsWales-CDRSourceTimestamp base: http://hl7.org/fhir/StructureDefinition/Extension version: 0.0.1 required: [value, valueDateTime]