📋 The Four Main Activities

1. 1Capture Data Requirements: Domain Modeling
2. 2Capture Functional Requirements: Use-Case Modeling
3. 3Capture Nonfunctional Requirements: Supplementary Specifications
4. 4Validate System Requirements: Review and verification

📦 Class Categories

• Business Objects: orders, accounts, invoices, contracts
• Real-World Objects and Concepts: suppliers, customers, employees, products
• Events: aircraft arrival/departure, sales, reservations, purchases, rentals

📝 Example: Finding Classes from Text

"The-system-must-be-able-to-record-which-movies-are-sold-and-rented-and-by-whom-(customer)."

Identified Classes:

• Movie - noun phrase
• Customer - noun implied by "by whom"

Identified Associations:

• Customer purchases Movie - "sold" indicates purchase relationship
• Customer rents Movie - "rented" indicates rental relationship

📝 Example: Extracting Attributes

"A sales clerk should be able to enter and update the following information about all customers: name, address, phone number, age, sex, and email address."

Class: Customer

Attributes identified:

• name
• address
• phoneNumber
• age
• sex
• email

📝 Example: Derived Association

    A ────X──── B ────Y──── C
    
    If association X means "A relates to B"
    And association Y means "B relates to C"
    
    Then we can DERIVE: A relates to C (through B)
    
    Therefore, if there's an association Z: A ────Z──── C
    It's a DERIVED association and should be eliminated!
                    

Why? Because Z is redundant - we can find the relationship between A and C by following X then Y.

📝 Complete Attribute Specification Example

Movie
- movieId: String
- title: String
- leadingActor[0..*]: String
- director: String
- producer: String
- genre: String
- synopsis: String
- releaseYear: Integer
- runningTime: Integer
- sellingPrice: Real
- rentalPrice: Real
- isPhysical: Boolean
- isDigital: Boolean
                

🎬 Movie Shop System Requirements

The following are the requirements for a web-based system to computerize the management of the sale and rental of movies for a movie shop:

1. The system must be able to handle both physical and digital movies.
2. It must be able to record which movies are sold and rented and by whom.
3. For sold movies, the quantity sold should be recorded; for physical movie rental, which copy is rented and when it is due back should be recorded.
4. The system should keep track of overdue rentals of physical movies and send email notices to customers who have movies overdue.
5. There will be a customer membership option for an annual fee, which will entitle a member to discounts (10%) on the sale and rental of movies.
6. Members should be able to make reservations for physical movie rentals either in person at the shop, by telephone or via the Web.
7. A member can reserve at most five physical movies at any one time, but there is no limit on how many physical movies a member or nonmember can rent at any one time.
8. As an added feature, the shop would like to allow customers (either members or nonmembers) to input, via the Web, mini-reviews (up to 100 words) and a rating (from 1, lowest, to 10, highest) of movies they have purchased or rented.
9. These reviews should be anonymous if the customer so wishes (i.e., customers can specify whether they want their name to be made known when other customers browse the reviews).
10. A sales clerk should be able to enter and update the following information about all customers (members or nonmembers): name, address, phone number, age, sex, and email address.
11. Members are assigned a membership number by the shop when they become members and a password, which allows them to change their personal information and to buy and rent digital movies via the Web.
12. The shop manager should be able to generate various reports on the sale and rental of movies.
13. A sales clerk should be able to sell and rent physical movies and process the return of rented physical movies.
14. When selling or renting physical movies, a sales clerk must be able to look up customer information and determine whether the customer is a member.
15. A sales clerk must be able to enter basic information about a movie (i.e., movie id, title, leading actor(s), director, producer, genre, synopsis, release year, running time, selling price, and rental price).

"The system must be able to handle both physical and digital movies."

Analysis:

• Classes: Movie
• Attributes:
  • Movie: isPhysical (Boolean)
  • Movie: isDigital (Boolean)

Reasoning: A movie can be both physical and digital, so we use boolean flags rather than creating separate subclasses.

"It must be able to record which movies are sold and rented and by whom."

Analysis:

• Classes & Associations:
  • Customer Purchases Movie
  • Customer Rents Movie

Reasoning: "by whom" implies a Customer class, and the verbs "sold" and "rented" create associations.

"For sold movies, the quantity sold should be recorded; for physical movie rental, which copy is rented and when it is due back should be recorded."

Analysis:

• Classes: RentalCopy
• Associations:
  • Movie HasPhysical RentalCopy
  • Customer RentsPhysical RentalCopy
• Attributes:
  • Purchases: quantity (Integer) - association class attribute
  • RentalCopy: copyNumber (String)
  • RentalCopy: returnDate (Date)

Reasoning: We need a RentalCopy class to track individual physical copies. Quantity belongs to the Purchase association.

"The system should keep track of overdue rentals of physical movies and send email notices to customers who have movies overdue."

Analysis:

• Attributes: Customer: email (String)

Reasoning: Email is needed for notification. Overdue status can be derived from returnDate.

"There will be a customer membership option for an annual fee, which will entitle a member to discounts (10%) on the sale and rental of movies."

Analysis:

• Generalization: Member is a kind of Customer
  • Customer Generalizes Member

Reasoning: Member is a specialized type of Customer with additional attributes and privileges.

"Members should be able to make reservations for physical movie rentals either in person at the shop, by telephone or via the Web."

Analysis:

• Association: Member Reserves RentalCopy

Reasoning: Only members can make reservations. The method (in person, phone, web) is not part of the domain model.

"A member can reserve at most five physical movies at any one time, but there is no limit on how many physical movies a member or nonmember can rent at any one time."

Analysis:

• Constraints:
  • max-card(Member, Reserves) = 5
  • max-card(Customer, RentsPhysical) = *

Reasoning: Multiplicity constraints capture business rules about quantity limits.

"As an added feature, the shop would like to allow customers (either members or nonmembers) to input, via the Web, mini-reviews (up to 100 words) and a rating (from 1, lowest, to 10, highest) of movies they have purchased or rented."

Analysis:

• Classes: Review
• Associations:
  • Customer Provides Review
  • Review IsFor Movie
• Attributes:
  • Review: reviewText (String)
  • Review: rating (Integer)

Reasoning: Review is a separate class because it has multiple attributes and relates two other classes.

"These reviews should be anonymous if the customer so wishes (i.e., customers can specify whether they want their name to be made known when other customers browse the reviews)."

Analysis:

• Attributes: Review: anonymous (Boolean)

Reasoning: A flag to indicate if the review should display the customer's name.

"A sales clerk should be able to enter and update the following information about all customers (members or nonmembers): name, address, phone number, age, sex, and email address."

Analysis:

• Attributes:
  • Customer: name (String)
  • Customer: address (String)
  • Customer: phoneNumber (String)
  • Customer: age (Integer)
  • Customer: sex (String)
  • Customer: email (String)

Reasoning: Direct mapping from requirements to attributes.

"Members are assigned a membership number by the shop when they become members and a password, which allows them to change their personal information and to buy and rent digital movies via the Web."

Analysis:

• Attributes:
  • Member: memberNumber (String)
  • Member: password (String)

Reasoning: These attributes are specific to Member, not all Customers.

"The shop manager should be able to generate various reports..."

"A sales clerk should be able to sell and rent physical movies..."

"When selling or renting physical movies, a sales clerk must be able to look up customer information..."

Analysis:

• No new domain model requirements

Reasoning: These are functional requirements describing what users can DO, not data that needs to be stored.

"A sales clerk must be able to enter basic information about a movie (i.e., movie id, title, leading actor(s), director, producer, genre, synopsis, release year, running time, selling price, and rental price)."

Analysis:

• Attributes:
  • Movie: movieId (String)
  • Movie: title (String)
  • Movie: leadingActor[0..*] (String) - multiple actors possible
  • Movie: director (String)
  • Movie: producer (String)
  • Movie: genre (String)
  • Movie: synopsis (String)
  • Movie: releaseYear (Integer)
  • Movie: runningTime (Integer)
  • Movie: sellingPrice (Real)
  • Movie: rentalPrice (Real)

Reasoning: Note that leadingActor has multiplicity [0..*] because a movie can have multiple leading actors.

Customer ─────Purchases────→ Movie
         (quantity)
         
Customer ─────Rents────→ Movie

Constraint: If Purchases is an association class, 
then a customer can purchase a given movie at most once.
                

Pros: Simple, direct

Cons: Cannot track multiple purchases of same movie, cannot track rental history

Customer ─────Has────→ Purchase ─────HasPurchase────→ Movie
                       (quantity)

Customer ─────Has────→ Rental ─────HasRental────→ Movie

Advantage: Can track multiple transactions over time
Can store transaction dates, amounts, etc.
                

Pros: More flexible, tracks history, allows multiple purchases

Cons: More complex

Customer ─────HasTransaction────→ Transaction ─────Has────→ Movie
                                       ▲
                                       │
                          ┌────────────┴────────────┐
                          │                         │
                      Purchase                   Rental

Advantage: Most general, allows easy addition of new transaction types
                

Pros: Extensible, unified handling of transactions

Cons: Most complex, may be over-engineered