900 B
The clinical record of a session is separate from its visit record
PatientSession already means "an attended visit that gets billed" — it is created when an
Appointment is confirmed and owns services, insurance shares, discounts and payments. A Treatment
Session, by contrast, exists from the moment a course is planned, long before any booking, and must
survive reschedules. So the two stay separate: a Treatment Session holds the plan and the clinical
record (its area records, devices and readings) and carries no money, while the Visit Record keeps
the financial side and is reached through the Appointment.
Consequences
A session's full picture spans four records — case, session, appointment, visit — so queries are longer. In exchange, neither side can silently become a second source of truth for the other. Any money field appearing on a Treatment Session is a design error.