Library book borrowing sequence flow orchestrates seven steps from student request through final confirmation, coordinating UI, controller, account validation, loan management, and database operations. The LibraryController acts as the central orchestrator, routing requests through AccountManager for credential validation, LoanManager for borrowing limit checks and loan execution, and BookDatabase for availability verification. This layered architecture enforces business rules—account status and borrowing limits—before executing the loan transaction and triggering NotificationService to confirm the borrowing event. Fork this diagram on Diagrams.so to customize validation rules, add payment processing, or extend notification channels for your institution's requirements.