03 - Domain Modeling

Question 1

What is domain modeling in software engineering?

Answer 1

Domain modeling is the process of capturing the most important classes and their associations in a software system.

Question 2

How do you capture data requirements in domain modeling?

Answer 2

Data requirements are captured using a class diagram, which represents the classes and associations in the software system.

Question 3

What are the potential classes in a class diagram?

Answer 3

Potential classes in a class diagram are derived from the nouns and noun phrases extracted from the prompt statement or user requirements

Question 4

How do you identify associations in a class diagram?

Answer 4

Associations in a class diagram are derived from the verbs and verb phrases extracted from the prompt statement or user requirements.

Question 5

What should you consider when decomposing user requirements into classes and associations?

Answer 5

The decomposition of user requirements depends on judgment, experience, and the nature of the problem. There is usually no single correct model, and design choices are based on individual judgment and experience.

Question 6

What are attributes in a class diagram?

Answer 6

Attributes are properties or characteristics of classes and are usually expressed as nouns followed by possessive phrases.

Question 7

How do you identify attributes in a class diagram?

Answer 7

Attributes can be obtained from the prompt statement or user requirements, but some may require consultation with domain experts

Question 8

How do you handle irrelevant classes in domain modeling?

Answer 8

• Irrelevant classes can be ignored by applying certain rules:
  
  • Eliminate classes that are irrelevant to the domain model.
  • Ignore vague classes and make them more specific.
  • Keep the most descriptive class if there are redundant classes.
  • Convert classes that describe a row into association names instead of classes.
  • Eliminate classes that represent operations, actions, or functionality.
  • Exclude classes that describe implementation constructs.

Question 9

Is there a single correct decomposition of user requirements in domain modeling?

Answer 9

No, there is usually no one correct decomposition. Design choices are subjective and based on judgment and experience.

Question 10

What is the importance of domain modeling in software engineering?

Answer 10

Domain modeling helps in understanding the structure and relationships of classes in a software system, which is crucial for effective software design and development.

Question 11

What should be done if some associations in a class diagram are irrelevant to the domain model?

Answer 11

Irrelevant associations that do not contribute to the understanding of the domain model should be eliminated to keep the diagram clean and focused.

Question 12

What should be done if some associations represent operations rather than relationships?

Answer 12

Associations that represent operations (e.g., actions or processes rather than static relationships between entities) should also be removed from the class diagram.

Question 13

Why is it generally advised to avoid ternary associations in a class diagram?

Answer 13

Ternary associations (associations involving three entities) can make diagrams more complex and harder to read. It is often better to decompose them into multiple binary associations to simplify the diagram.

Question 14

When is it acceptable to remove a derived association?

Answer 14

Derived associations, where the relationship between two entities can be inferred from other associations, can be removed if they provide redundant information. For example, if you can reach from entity A to B through an indirect path (A to C to B) and directly (A to B), you might remove one path if it doesn’t add additional value.

Question 15

How should redundant paths in a class diagram be managed?

Answer 15

Redundant paths should be carefully evaluated. In cases where paths provide different meanings or roles (e.g., indicating different aspects of transactions or relationships), both paths might be necessary to retain meaningful information.

Question 16

What example illustrates the need to retain redundant paths?

Answer 16

The example provided involves transactions where two associations (isAgainst and holds) are present along with a makes association. Removing one path might cause loss of information about transaction initiation or account involvement, thus both associations are needed.

Question 17

What should be done if attributes in a class diagram are not related to the class or object they are associated with?

Answer 17

Attributes that are not closely related to the class or object should be removed. The class should be simple and coherent, with attributes directly relevant to its role

Question 18

How should attributes that are actually classes or should be in an association class be handled?

Answer 18

Attributes that are better represented as classes should be transformed into classes. Similarly, attributes that pertain to relationships between classes should be moved to an association class, which holds attributes relevant to the association.

Question 19

What details must be specified for each class in a class diagram?

Answer 19

For each class, you must specify all attributes, including their names, types, and multiplicities.

Question 20

What should be provided for each association in a class diagram?

Answer 20

For each association, you should provide a name, and if it is a unary association, you should also include role names and multiplicities. If necessary, include an association class to detail attributes related to the association.