 What to do if you want to build a new house? › Buy a bunch of wood and nails and start immediately. › Or, put some blueprints to follow, and plan of the steps. In software world this is called a Model

 Is the process of taking the information from the model and displaying it graphically using a standard set of graphical elements.  Standardization is vital in visual modeling. › Ease communication: between users, developers, analysts, testers, managers, etc.  Very important in the Information Systems development process: › Show how the system works on several levels. › Model the interactions between the users and a system, interactions of objects within a system, and the interactions between other systems.

 A general-purpose, developmental, modeling language in the field of software engineering, that is intended to provide a standard way to visualize the design of a system.

 Behavioral UML Diagrams: › Use case diagram. › Activity diagram. › Sequence diagram. › Timing diagram.  Structured UML Diagrams: › Class diagram. › Object diagram. › Component diagram. › Deployment diagram.

 Use Case diagrams show the interactions between use cases and actors.  Use cases represent system functionality, the requirements of the system from the user's perspective.  They are useful for presentations to management and project stakeholders.

1. Use cases. 2. Actors. 3. Relationships 4. System boundary boxes (optional).

 A use case describes a sequence of actions that provide something of measurable value to an actor and is drawn as a horizontal ellipse.  a use case illustrates how someone might use the system.

 An actor is a person, organization, or external system that plays a role in one or more interactions with your system.  Actors are drawn as stick figures.  Actors are anything that is outside the system's scope  types of actors: › users of the system › other systems that will interact with the system being built

 Association Relationship (actor and use case)  An association relationship is a relationship between an actor and a use case.  It indicates that a particular actor initiates the functionality provided by the use case.

 Includes Relationship (use case and use case)  Include relationship show that the behavior of the included use case is part of the including (base) use case.  The base use case is incomplete without the included use case.  The included use case is mandatory and not optional.

 Extends Relationship (use case and use case)  An extends relationship allows one use case the option to extend the functionality provided by another use case. if and only if  While the "Change Reservation" use case is running, "Check Credit" runs if and only if the amount of the reservation has changed.  Because "Check Credit" is optionally run, there is an extends relationship between the use cases.  The arrow is drawn from the use case that is optionally run to the use case that is being extended.

 Generalization (actor and actor) or (use case and use case)

 You can draw a rectangle around the use cases, called the system boundary box, to indicates the scope of your system.  Anything within the box represents functionality that is in scope and anything outside the box is not.

 A book is written by an author, published by a publisher, sold by a book store, and buy or borrow by a reader. Moreover, for a reader to read a book, he might buy or borrow it from a book store that is selling it. Draw a use case diagram for this scenario, showing relationships between different use cases.