It allows the definitions of the structures to be shared and published through repositories of structure definitions, compared with each other, and used as the basis for code, report and UI (User Interface) generation. The Structure Definition resource has a set of metadata that is mostly shared with the Value Set, Capability Statement and other infrastructure resources.
Structures are able to map elements to concepts in other definition systems. Generally, these are used to map the elements to local implementation models, data paths, and concepts. However they are also used to map to other standards and published terminologies.
StructureDefinitions are used to define the basic structures of FHIR: data types, resources, extensions, and profiles. The same definition structure can also be used to define any arbitrary structures that are a directed acyclic graph with typed nodes, where the primitive types are those defined by the FHIR specification.
This technique has many uses:
– Describing any arbitrary content model
– Describing existing HL7 content models (e.g. v2, CDA) using FHIR
– Describing common design patterns used in FHIR
– Defining a content model to support the mapping language