History

Endpoints Implemented

1. Get Specific Version (vread)

GET /fhir/{bucket}/{resourceType}/{id}/_history/{versionId}

Example

GET http://localhost:8080/fhir/acme/Patient/1234/_history/2

Implementation

• Direct KV GET from Versions collection
• Key format: Patient/1234/2
• Fast, single KV operation

2. Get Complete History

GET /fhir/{bucket}/{resourceType}/{id}/_history?_count={count}&_since={date}

Example

GET http://localhost:8080/fhir/acme/Patient/1234/_history
GET http://localhost:8080/fhir/acme/Patient/1234/_history?_count=20
GET http://localhost:8080/fhir/acme/Patient/1234/_history?_since=2025-01-01T00:00:00Z

Everything

Overview

The $everything operation returns all resources related to a specific patient. This is a powerful FHIR operation that provides a comprehensive view of a patient's clinical data.

Endpoints

Instance-Level Operation (Supported)

GET /fhir/{bucket}/Patient/{id}/$everything

• Returns all resources for a specific patient.

Type-Level Operation (Not Supported)

GET /fhir/{bucket}/Patient/$everything

• This is NOT supported. The operation requires a specific patient ID.

Query Parameters

Parameter	Type	Description	Example
start	Date	Start date filter for clinical resources	?start=2023-01-01
end	Date	End date filter for clinical resources	?end=2024-12-31
_type	String	Comma-separated list of resource types to include	?_type=Observation,Condition
_since	DateTime	Only resources updated after this instant	?_since=2024-01-01T00:00:00Z
_count	Integer	Maximum number of resources to return (default: 50, max: 200)	?_count=100

Resource Types Included

The operation searches across the following resource types (in order of clinical relevance):

1. Observation - Lab results, vital signs, etc.
2. Condition - Diagnoses, problems
3. Encounter - Visits, admissions
4. Procedure - Surgical procedures, treatments
5. DiagnosticReport - Lab reports, imaging reports
6. MedicationRequest - Prescriptions
7. Immunization - Vaccinations
8. ServiceRequest - Orders, referrals
9. DocumentReference - Clinical documents
10. General - Other resources

Implementation Strategy

1. Patient Validation

• KV Lookup: Direct key-value retrieval of Patient/{id} from the Patient collection
• Returns 404 Not Found if the patient doesn't exist

2. Resource Search

• FTS Queries: For each resource type, execute FTS queries to find resources that reference the patient
• Reference Fields: Always searches BOTH patient.reference OR subject.reference for all resource types
• Filters: Applies date range (start, end), update time (_since), and resource type (_type) filters
• Sorting: All results sorted by meta.lastUpdated DESC (newest first)

3. Batch Retrieval

• Grouping: Groups all matching keys by resource type
• KV Operations: Batch retrieves documents for each resource type (efficient!)
• Ordering: Returns resources in clinical relevance order

4. Bundle Construction

• Patient First: The patient resource is always first in the bundle
• Search Mode: Patient has mode=match, all others have mode=include
• Count Limiting: Respects the _count parameter (default: 50, max: 1000)

Examples

1. Get Everything for a Patient

GET http://localhost:8080/fhir/acme/Patient/1234/$everything

Response

{
  "resourceType": "Bundle",
  "type": "searchset",
  "total": 48,
  "entry": [
    {
      "fullUrl": "http://localhost:8080/fhir/acme/Patient/1234",
      "resource": {
        "resourceType": "Patient",
        "id": "1234",
        "name": [{ "family": "Smith", "given": ["John"] }]
      },
      "search": { "mode": "match" }
    },
    {
      "fullUrl": "http://localhost:8080/fhir/acme/Observation/5678",
      "resource": {
        "resourceType": "Observation",
        "id": "5678",
        "subject": { "reference": "Patient/1234" }
      },
      "search": { "mode": "include" }
    }
  ]
}

2. Filter by Resource Type

GET http://localhost:8080/fhir/acme/Patient/1234/$everything?_type=Observation,Condition

• Returns only Observations and Conditions.

3. Filter by Date Range

GET http://localhost:8080/fhir/acme/Patient/1234/$everything?start=2024-01-01&end=2024-12-31

• Returns only resources with clinical dates in 2024.

4. Limit Results

GET http://localhost:8080/fhir/acme/Patient/1234/$everything?_count=10

• Returns the patient + up to 9 related resources (10 total).

5. Get Recent Updates

GET http://localhost:8080/fhir/acme/Patient/1234/$everything?_since=2024-10-01T00:00:00Z

• Returns only resources updated since October 1, 2024.

Optimization Tips

1. Use _type parameter to search only needed resource types
2. Use _count parameter to limit results
3. Use _since parameter for incremental updates

Comparison with _include/_revinclude

Feature	$everything	_revinclude
Purpose	Get ALL patient data	Get specific related resources
Resource Types	10+ types automatically	1 type per parameter
Query	Single operation	Multiple includes needed
Use Case	Complete patient view	Specific relationships
Performance	Higher cost (10+ FTS queries)	Lower cost (1 FTS query)

When to use $everything

• Patient portals (complete record)
• Data export
• Clinical summaries
• Complete patient context

When to use _revinclude

• Specific queries (e.g., "patients with their observations")
• Better performance
• Targeted data retrieval