Week06 Flashcards
User Stories
A User Story is a one-sentence description of a work-related task done by a user to achieve some goal or result
The template for a user story description is:
“As a <role> I want to <goal> so that <benefit>”</benefit></goal></role>
Use Cases
Use Case Definition:
A use case is an activity that the system performs, typically in response to a request by a user. For example, in an online shopping system, a use case might be “placing an order” or “searching for a product.”
Use cases define functional requirements, which are the specific behaviors or functions that the system must support.
Functional Decomposition:
Analysts decompose the system into a set of use cases: This means that analysts break down the entire system into smaller, more manageable parts, each representing a different use case. This process is called functional decomposition. It helps in understanding the system’s functionality by looking at it from the user’s perspective.
Techniques for Identifying Use Cases:
User Goal Technique: This technique involves identifying the goals or objectives that users have when interacting with the system. Each goal can lead to the identification of one or more use cases.
Event Decomposition Technique: This technique focuses on identifying events that trigger the system to perform an action. Events can come from users, other systems, or time-based triggers, and each event corresponds to a use case.
User Goal Technique
Identify all of the potential categories of users of the system
Interview and ask them to describe the tasks the computer can help them with
Probe further to refine the tasks into specific user goals, “I need to Ship items, Track a shipment, Create a return”
User Goal TechniqueSome Users and Goals
User
potential customer
marketing manager
shipping personal
** User goal and resulting use cases**
search for item
fill shopping cart
view product rating and comments
add/update product infor
add/update promotion
produce sales history report
ship items
track shipment
create item return
User Goal Technique: Specific Steps
Identify all the potential users for the new system
Classify the potential users in terms of their functional role (e.g., shipping, marketing, sales)
Further classify potential users by organizational level (e.g., operational, management, executive)
For each type of user, interview them to find a list of specific goals they will have when using the new system
Create a list of preliminary use cases organized by type of user
Identify where different types of users need the same use cases
Review the completed list with each type of user and then with interested stakeholders
Event Decomposition Technique
More Comprehensive and Complete Technique
Identify the events that occur to which the system must respond.
For each event, name a use case (verb-noun) that describes what the system does when the event occurs
Event– something that occurs at a specific time and place, can be described, and should be remembered by the system
Types of Events
External Event
an event that occurs outside the system, usually initiated by an external agent or actor
Temporal Event
an event that occurs as a result of reaching a point in time
State Event
an event that occurs when something happens inside the system that triggers some process
reorder point is reached for inventory item
Use Cases and Brief Use Case Descriptions
Brief use case description is often a one sentence description showing the main steps in a use case
use case create customer account
look up customer
process account adjustmet
brief use case des
user/actor enters new customer account data,and the sytem assigns account no,creates a customer record, and creates an account record
user/actor enters customer account no, and the sytem retrives displays customer and account data
user/actor enters order no, and the sys retrives customer and order data:
actor enters adjustment amount and the sys creates a transaction record for adjustments
Use Case Diagrams
Use case diagram - a UML model used to graphically show use cases and their relationships to actors
UML is Unified Modeling Language, the standard for diagrams and terminology for developing information systems
Use Case Diagrams: Steps
- Identify Stakeholders and Users: Determine who will benefit from viewing the use case diagram.
-
Assess Needs: Understand what each stakeholder or user needs to review in the diagram—consider subsystems, user types, and specific use cases of interest
. - Select and Draw: Choose the relevant use cases and actors for each communication need and draw the diagram using suitable software.
- Name and Review: Give each use case diagram a clear name and note how and when it should be used for reviews with stakeholders and users.
