The Patient Repository persists demographics, identifiers and merge lineage for each EMPI record. It is the durable source for FHIR Patient reads.
Storage profile
PostgreSQL with row-level encryption for identifier columns; retention follows HIPAA policy.
The schema is small and audit-oriented. The ERD is embedded on the Overview tab.
PATIENT.id is the internal EMPI key; external MRNs live in IDENTIFIER rows with assigning authority.MERGE_HISTORY so compliance can reconstruct lineage.golden record survives a merge; source ids are tombstoned, not deleted.