Hospital chain information system ER diagram models a multi-hospital network with regional health authorities (ASL), hospitals, departments, medical staff, and patient records. Data flows from organizational entities (ASL, OSPEDALE, REPARTO) through personnel (MEDICO, DIREZIONE_REPARTO) to patient care (PAZIENTE, RICOVERO, SOMMINISTRAZIONE) and pharmaceutical management (FARMACO, CASA_FARMACEUTICA). The schema enforces referential integrity across 12 entities with primary and foreign keys, capturing admission history, medication dosing, and physician assignments. Fork this diagram to customize for regional health networks, add audit trails, or adapt for Kubernetes-based healthcare data platforms. The associative tables (MEDICO_REPARTO, SOMMINISTRAZIONE) enable flexible many-to-many relationships critical for hospital operations.