fhir

Ingesting and Processing FHIR Objects

This directory demonstrates how to ingest FHIR messages. The relevant files are:

• fhir.schema.json: The FHIR 4.0 JSON schema, dowloaded from https://www.hl7.org/fhir/downloads.html
• fhir.bundle.json: The layered schema bundle defining all entities in the FHIR schema
• simplebundle.json: A sample FHIR bundle resource
• patient.json: A sample FHIR patient resource

The Layered Schema Bundle

This file defines the layered schemas that will be created based on the FHIR schema. It contains entries of the form:

{
    "typeNames" : {
        "Patient": {
            "jsonSchema": {
                "ref": "fhir.schema.json#/definitions/Patient",
                "layerId": "https://hl7.org/fhir/Patient"
            }
        },
        "Bundle": {
            "jsonSchema": {
                "ref": "fhir.schema.json#/definitions/Bundle",
                "layerId": "https://hl7.org/fhir/Bundle"
            }
        },
       ...

This snippet shows two entities named Patient and Bundle. The JSON schema definitions for these entities are given in the jsonSchema.ref key. For Patient, the schema definition is in the fhir.schema.json file, at location /definitions/Patient:

fhir.schema.json:
{
  ...
  "definitions": {
    ...
    "Patient": {
      "description": "Demographics and other administrative information ...",
      "properties": {
        "resourceType": {
          "description": "This is a Patient resource",
          "const": "Patient"
        },
        "id": {
        ...

Using this JSON schema, layers generates a new schema base. That schema base is assigned the id given in "layerId": "https://hl7.org/fhir/Patient".

For example, to ingest a FHIR resource of type Patient:

layers ingest json --bundle fhir.bundle.json --type Patient patient.json

This operation does the following:

• Reads fhir.bundle.json, and generates layered schemas for each typename
• Ingests patient.json file using the layered schema for Patient

Ingesting FHIR messages

To ingest a sample patient, use:

layers ingest json --bundle fhir.bundle.json --type Patient patient.json

This will ingest the Patient record based on the schema with data nodes connected to schema nodes using ls:instanceOf edges.

layers ingest json --bundle fhir.bundle.json --type Patient patient.json --embedSchemaNodes

This will ingest Patient record, merging schema nodes with data nodes.

Similarly, to ingest a FHIR Bundle:

layers ingest json --bundle fhir.bundle.json --type Bundle simplebundle.json --embedSchemaNodes

The result of this operation can be seen in bundle.png or bundle.svg.

Note that the FHIR bundle contains a polymorphic array containing different entities. The layered schemas used to ingest those entities are define in the fhir.bundle.json file.