History/audit tracking

Without a history table or audit log, a booking system cannot answer the most basic support questions: "who cancelled my appointment?", "when was this booking confirmed?", or "was the reschedule requested by the customer or the provider?". ISO 25010:2011 maintainability requires that state changes are traceable. In regulated contexts (medical scheduling, legal appointments, financial services), audit trails are legally required. Even in unregulated systems, the inability to reconstruct booking history turns routine customer disputes into unresolvable conflicts and forces manual database forensics for every support ticket.

Create a BookingLog table and write a transition record on every status change. Add the model in prisma/schema.prisma and call the log function from your booking service.

// schema.prisma
model BookingLog {
  id          String   @id @default(cuid())
  bookingId   String
  fromStatus  String
  toStatus    String
  actorId     String
  createdAt   DateTime @default(now())
}

// booking-service.ts — call on every transition
async function logTransition(bookingId: string, from: string, to: string, actorId: string) {
  await db.bookingLog.create({
    data: { bookingId, fromStatus: from, toStatus: to, actorId }
  });
}