Information systems analysis and requirements analysis produces a requirements specification. This specification states the project goal and the related data storage, data movement

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Use Case Diagrams
Information System Requirements Analysis
Information systems analysis and requirements analysis produces a requirements
specification. This specification states the project goal and the related data
storage, data movement, security, quality, usage, functional and non-functional
requirements that must be achieved in order to achieve the business goal stated in
the business case.
Use Case Diagrams
Use Case diagram is a graphical representation of the high-level system scope. It
includes use cases, which are pieces of functionality the system will provide, and
actors, who are the users of the system. Looking at a Use Case diagram, you
should easily be able to tell what the system will do and who will interact with it.
Use cases define the system, They show interactions between actors and the
system to create a working structure. Although you might break them down to
smaller components, uses cases will show:
• Actors: Actors are the users that interact with the system, can be human
roles or system. Another word actor is a person, system, piece of hardware,
or other thing that interacts with your system. It is denoted with a
stick figure. We differentiate active actors, who initiate interactions
with a system.
• Use Case: A use case represents a function or an action within
the system. Its drawn as an oval and named with the function.

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Use Case Diagrams
• System: System is used to define the scope of the use case and drawn as a
rectangle. This an optional element but useful when your
visualizing large systems. For example you can create all the
use cases and then use the system object to define the scope
covered by your project.
Example: Consider an auction website (eBay)
• The actor customer might:
- Register for an account
- Search for items by keyword
- Place a bid on an item
- Put an item up for auction
- Check the status of this item
Figure 3.1. Case study website

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Use Case Diagrams
• Includes relationship: An includes relationship suggests that one use case
must include another. In other words, running one use case means that the
other must be run as well. One use case may be included by one or more
other use cases. It is denoted by a dashed unidirectional arrow from the
source use case(s) to the target use case.
• Extends relationship: An extends relationship is used when one use case
optionally extends the functionality provided by another. In other words, if
one use case runs, an extending use case may or may not run.
Example: Consider an auction Phone Operator:
- The actor Phone Operator might:
• Select Customer
o Search Customer
• Create Order
o Add Delivery Address
o Select Delivery Option
• Select Products
o Search Products
o Select size

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Use Case Diagrams
Figure 3.2. Case study phone operator