AQL Query Builder

The Archetype Query Language (AQL) is how you query openEHR data across EHRs. Writing it as concatenated strings is error-prone, so oehrpy provides a fluent builder that assembles SELECT, FROM, CONTAINS, WHERE, ORDER BY and paging clauses for you. Run the result with the EHRBase client.

Basic Queries

from oehrpy.aql import AQLBuilder

# Simple query
query = (
    AQLBuilder()
    .select("c/uid/value", alias="composition_id")
    .select("c/name/value", alias="name")
    .from_ehr()
    .contains_composition()
    .where_ehr_id()
    .build()
)

print(query.to_string())
# SELECT c/uid/value AS composition_id, c/name/value AS name
# FROM EHR e CONTAINS COMPOSITION c
# WHERE e/ehr_id/value = :ehr_id

Complex Queries

# Query with observations and ordering
query = (
    AQLBuilder()
    .select("c/context/start_time/value", alias="time")
    .select("o/data[at0001]/events[at0006]/data[at0003]/items[at0004]/value/magnitude",
            alias="systolic")
    .from_ehr()
    .contains_composition()
    .contains_observation(archetype_id="openEHR-EHR-OBSERVATION.blood_pressure.v1")
    .where_ehr_id()
    .order_by_time(descending=True)
    .limit(100)
    .build()
)