📚 CS340 Chapter 2 Exam

A weak entity type always has a _______ participation constraint with respect to its identifying relationship.

The disjoint constraint in the EER model specifies that:

Which of the following best describes specialization in EER diagrams?

What symbol is used in EER diagrams to represent the subset (IS-A) relationship?

In a total specialization constraint:

Which of the following statements about generalization is TRUE?

A union type (category) in EER diagrams:

What is the difference between overlapping and disjoint constraints?

In an EER diagram, a subclass discriminator attribute:

Which of the following is TRUE about attribute inheritance in EER?

Explain the difference between specialization and generalization in EER modeling. Provide an example for each.

What is a weak entity type? Describe the characteristics that distinguish it from a regular (strong) entity type.

At a weekend retreat, the entity type PERSON has three subclasses: CAMPER, BIKER, and RUNNER. Describe how you would model the following scenario using EER notation:

"At a given time, a person may or may not be one of these subclasses. However, a person may be any two (or even three) of these subclasses at the same time."

What constraints would you use (disjoint/overlapping, total/partial)?

Explain what a "category" (union type) is in EER modeling and provide a real-world example where it would be appropriate to use.

Which of the following statements about shared subclasses is TRUE? (Select all that apply)

A university hospital is implementing a patient management system. Doctors are categorized into three types: General Practitioner, Surgeon, and Specialist. A doctor must belong to at least one type but can belong to multiple types at once.

Describe the EER modeling approach you would use. Specify:

• Whether this is specialization or generalization
• Whether to use disjoint or overlapping constraint
• Whether to use total or partial participation
• Justify your choices

In EER diagrams, what does a double-lined rectangle represent?

What is the purpose of using a discriminator attribute in specialization? Give an example.

Consider a library database where BOOK is an entity with subclasses HARDCOVER, PAPERBACK, and EBOOK. A book can only be one of these types. What constraints would you apply and why?

Which notation is used to show total specialization in an EER diagram?

Explain the concept of participation constraints in identifying relationships for weak entities. Why must a weak entity have total participation?

Identify at least THREE errors in the following EER design description:

"A COPY entity is defined with its own primary key (copy_number). It does not have a total participation constraint with the BOOK entity. The LIBRARY entity is shown as a subclass of BUILDING, and the BORROWER entity has partial participation in the LOAN relationship."

Derived attributes in EER diagrams are shown using:

Design an EER schema for the following scenario:

"A company tracks VEHICLES which can be CARS or TRUCKS. Some vehicles are COMPANY_OWNED and others are LEASED. A vehicle can be both a car and company-owned, or a truck and leased, etc."

Describe your design approach, including what constraints you would use and why.

Compare and contrast the following pairs of EER concepts:

• Specialization vs. Generalization
• Disjoint vs. Overlapping constraints
• Total vs. Partial specialization
• Strong vs. Weak entities

Provide examples for each.