Don’t be daunted by the FHIR documentation.
Start with these 7 key concepts. If you’re new to FHIR, try to understand them well enough that you can explain them to someone else.
1. Resource References
FHIR resources rarely exist in isolation. Resources connect to each other via Resource References, which are links to other resources. Usually — but not always — on the same FHIR server.
http://hl7.org/fhir/R4/references.html#Reference
2. CodeableConcepts
Each CodeableConcept represents a single ‘Concept’ or entity that is represented by one or more ‘Code’ or terms. This is one of the most common and important data types in FHIR.
http://hl7.org/fhir/R4/datatypes.html#CodeableConcept
3. An Element’s Cardinality
This tells you how many of an element there can be. Take Condition as an example. It MUST contain one and ONLY one ‘subject’ element (1 .. 1). And there can be any number of ‘identifier’ elements, even none (0 .. *).
https://darrendevitt.com/fhir-a-refresher-on-cardinality/
4. Identifiers
Most FHIR resource types have an Identifier element. These are business identifiers and do not come from the FHIR server itself. It’s important to understand the difference between Identifiers and FHIR IDs.
https://darrendevitt.com/fhir-ids-and-identifiers/
5. _include and _revInclude Query Parameters
It’s rare you’ll write a FHIR query that returns only a single resource. The _include and _revInclude parameters give you easy access to resources linked to and from the resource you’re looking for.
https://learn.microsoft.com/en-us/azure/healthcare-apis/fhir/search-samples#search-result-parameters
6. Data Types
There are 58 data types in FHIR. They’re the building blocks that come together to make up resources. You don’t need to know them all, but a broad understanding of their diversity and how they connect to each other is important.
https://darrendevitt.com/data-types-the-building-blocks-of-fhir/
7. GET, POST and PUT requests
How to get, create or update a FHIR resource. In code or via an API client such as Postman. There’s also a PATCH request, but you can ignore that for a while. 🙂
https://www.hl7.org/fhir/R4/http.html
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