The document discusses a use case diagram for an online library management system. It defines key elements of a use case diagram including actors, use cases, associations, and system boundaries. It then provides an example use case diagram for an ATM machine with users and constraint checker as actors and use cases such as insert ATM card, enter pin, and provides cash.

1. USE CASE DIAGRAM FOR
ONLINE LIBRARY
MANAGEMENT SYSTEM
S.NITHISH KUMAR
2021503530

2. USE CASE DIAGRAM
A use case diagram is a type of Unified Modeling Language (UML) diagram that is used to visualize
the interactions between various actors (which can be individuals, other systems, or external entities)
and a system to achieve specific goals or functionalities. Use case diagrams are primarily used to
represent the functional requirements of a system from an external user's perspective. They provide a
high-level view of the system's behavior and the ways in which different actors interact with it.
Key elements and concepts in a use case diagram include:
Actor: An actor is an external entity, which can be a user, another system, or some other entity that
interacts with the system. Actors are represented as stick figures or other simple shapes on the
diagram.
Use Case: A use case represents a specific functionality or feature that the system provides to its
actors. Use cases are depicted as ovals on the diagram and are connected to actors to show the
interactions.
Association: Lines or connectors are used to illustrate the relationships or associations between
actors and use cases. These lines show that an actor interacts with one or more use cases.
System Boundary: A boundary or box around the use cases and actors is used to represent the
system itself. It demarcates the system's scope and shows which elements are internal and external to
the system.

3. USE CASE DIAGRAM FOR
ONLINE LIBRARY MANAGEMENT
SYSTEM

4. USE CASE DIAGRAM FOR
ONLINE LIBRARY
MANAGEMENT SYSTEM
The actors used in the diagram are
•User
•Constraint checker
•Cash provider
The Use cases used in the diagram are
•Insert ATM card
•Select language
•Enter pin
•Enter amount
•Provides cash
•Transaction status
•Notification