Week 7: Object Modeling & System Diagrams

What is object modeling?

A technique that represents a system as a collection of interacting objects rather than isolated processes.

What is the main goal of object modeling?

To produce an object-oriented system diagram.

What does object modeling focus on?

Real-world things managed by a system.

What is encapsulation in object modeling?

Combining data structures and operations within an object.

What are examples of system objects?

Student, Teacher, Course, and Product.

What are the six core learning outcomes of object modeling?

Define modeling, identify objects, identify attributes and methods, map relationships, create class diagrams, and interpret models.

What is an object?

An entity with identity, attributes, and behavior.

What is the formula for an object?

Object = Data (Attributes) + Behavior (Methods).

What is object identity?

A unique identifier that distinguishes an object from other objects.

What are attributes?

Data or properties that describe an object's state.

What are behaviors?

Actions or operations that an object can perform.

What is a class?

A blueprint or template defining the characteristics and behaviors of objects.

What is an object?

An actual runtime instance created from a class template.

What analogy describes a class?

An architectural blueprint.

What analogy describes an object?

A concrete physical house.

What are the three core elements of a class definition?

Class name, attributes, and methods.

What is a class name?

A noun describing the entity type, usually singular and capitalized.

What are attributes in a class?

Variables that hold data values for each object instance.

What are methods in a class?

Functions that define the object's operational logic.

What are the three compartments of a UML class box?

Class name, attributes, and methods.

What belongs in the top compartment of a UML class box?

The class name.

What belongs in the middle compartment of a UML class box?

The attributes or data stored by each object instance.

What belongs in the bottom compartment of a UML class box?

The methods or functions performed by the object.

How should a UML class name be written?

As a singular, capitalized noun, such as Student.

How are attributes commonly written in UML?

attributeName: DataType.

How are methods commonly written in UML?

methodName().

What does a colon indicate in an attribute declaration?

The data type of the attribute.

What does a minus sign (-) commonly indicate in UML?

Private visibility.

What does a plus sign (+) commonly indicate in UML?

Public visibility.

What are the attributes of the Student example?

studentID: String, name: String, and email: String.

What are the methods of the Student example?

registerCourse() and viewGrade().

What are the attributes of a Student entity in the domain examples?

name, email, and gpa.

What are the methods of a Student entity in the domain examples?

register() and viewGrade().

What are the attributes of a User Account?

username and passwordHash.

What are the methods of a User Account?

login() and resetPassword().

What are the attributes of a Product?

productID, price, and stockQty.

What are the methods of a Product?

updatePrice() and reduceStock().

What are the attributes of an Order?

orderDate and totalAmount.

What are the methods of an Order?

calculateTotal() and cancel().

What is a system diagram?

A visual architectural model showing structural components, data containers, and interactions across software boundaries.

What is the primary system diagram in object-oriented analysis?

The UML Class Diagram.

What does a UML class diagram show?

Structural classes, attributes, methods, and class relationships.

What does UML stand for?

Unified Modeling Language.

What is UML?

A standard visual language for specifying, visualizing, constructing, and documenting software system artifacts.

What are common UML diagram types?

Class, Use Case, Sequence, Activity, and State diagrams.

Which UML diagram is the primary focus of this lesson?

The Class Diagram.

How can objects be identified from a problem scenario?

Highlight key domain nouns in the scenario.

What is the noun extraction strategy?

Reading problem scenarios and identifying nouns that represent potential classes or objects.

In the statement "A Customer places an Order containing multiple Products," what are the key nouns?

Customer, Order, and Product.

How can attributes be identified?

Ask what specific information must be stored for each entity.

What are example Customer attributes?

customerID, email, and billingAddress.

How can methods and behaviors be identified?

Locate action verbs in system specifications.

What is the verb extraction rule?

Use action verbs in requirements to identify object responsibilities and behaviors.

What question helps identify methods?

What actions can this object perform, or what processes are applied to it?

What are the attributes of the example Customer class?

customerID: String and name: String.

What are the methods of the example Customer class?

login(), updateProfile(), placeOrder(), and cancelOrder().

What is an association in UML?

A structural link connecting two classes and indicating that their objects interact.

What does an association represent?

A relationship between classes.

What is an example of an association between Student and Course?

A Student enrolls in a Course.

What is multiplicity in UML?

A specification of how many instances of one class can be linked to an instance of another class.

What does multiplicity 1 mean?

Exactly one.

What does multiplicity 0..1 mean?

Zero or one.

What does multiplicity 1..* mean?

One or more.

What does multiplicity 0..* mean?

Zero or many.

What is a one-to-one relationship?

A relationship where one instance of a class is associated with exactly one instance of another class.

What is an example of a one-to-one relationship?

Student and StudentID, with multiplicity 1 to 1.

What is a one-to-many relationship?

One instance of a class can be associated with multiple instances of another class.

What is an example of a one-to-many relationship?

One Customer can have zero or many Orders.

What is a many-to-many relationship?

A relationship where multiple instances of each class can be associated with multiple instances of the other class.

How can a many-to-many relationship be resolved?

Introduce an intermediate class, such as Enrollment, between the two classes.

How is the Student-Course many-to-many relationship resolved?

Student (1) to Enrollment (0..*) to Course (1), with Enrollment records linking students and courses.

What are the three classes in the complete enrollment model?

Student, Enrollment, and Course.

What are the attributes of Student in the enrollment model?

studentID, name, and email.

What are the methods of Student in the enrollment model?

register() and viewGrade().

What are the attributes of Enrollment in the enrollment model?

enrollmentID, date, and status.

What are the methods of Enrollment in the enrollment model?

enroll() and cancel().

What are the attributes of Course in the enrollment model?

courseID, courseName, and units.

What are the methods of Course in the enrollment model?

addCourse() and update().

What is the multiplicity between Student and Enrollment?

One Student can have zero or many Enrollment records; each Enrollment belongs to one Student.

What is the multiplicity between Course and Enrollment?

One Course can have zero or many Enrollment records; each Enrollment refers to one Course.

What is Step 1 in producing a system diagram?

Understand the system and its requirements.

What is Step 2 in producing a system diagram?

Identify objects.

What is Step 3 in producing a system diagram?

Identify attributes.

What is Step 4 in producing a system diagram?

Identify methods.

What is Step 5 in producing a system diagram?

Identify links or associations.

What is Step 6 in producing a system diagram?

Set multiplicity constraints.

What is Step 7 in producing a system diagram?

Draw the diagram.

What are the seven steps to produce a system diagram?

Understand the system, identify objects, identify attributes, identify methods, identify links, set multiplicity, and draw the diagram.

What is the scenario in the enrollment modeling walkthrough?

A student uses an online enrollment system to select and register in courses.

What objects are identified in the enrollment walkthrough?

Student, Course, and Enrollment.

What attributes are extracted for Student in the walkthrough?

id and name.

What attributes are extracted for Course in the walkthrough?

code and title.

What attributes are extracted for Enrollment in the walkthrough?

date and status.

What methods are added in the enrollment walkthrough?

register(), addCourse(), and cancelEnrollment().

What associations are established in the enrollment walkthrough?

Student links to Enrollment, and Enrollment links to Course.

What are the multiplicities in the enrollment walkthrough?

One Student to zero or many Enrollments; one Course to zero or many Enrollments.

What is the purpose of rendering UML class boxes and connectors?

To present the classes, their contents, and their relationships in a complete diagram.

What are the system requirements of the Online Library System case study?

Students search, borrow, and return books; librarians manage catalog items and process borrowing records.

What classes are identified in the Online Library System case study?

Student, Book, Librarian, and BorrowingRecord.

What does Student represent in the library system?

The borrower.