Primitive type 'ruid'
HL7 Reserved Identifier Scheme (RUID)\nA globally unique string defined exclusively by HL7. Identifiers in this scheme are only defined by balloted HL7 specifications. Local communities or systems must never use such reserved identifiers based on bilateral negotiations. HL7 reserved identifiers are strings that consist only of (US-ASCII) letters, digits and hyphens, where the first character must be a letter. HL7 may assign these reserved identifiers as mnemonic identifiers for major concepts of interest to HL7.
Note that FHIR strings SHALL NOT exceed 1,048,576 (1024*1024) characters in size
All FHIR elements must have a @value or children
hasValue() or (children().count() > id.count())
An identifier that starts with a letter and contains any combination of letters, numbers, and hyphen.
unique id for the element within a resource (for internal references)
Must have either extensions or value[x], not both