CS 340 Chapter 3 - EER Comprehensive Exam (30 Questions)

Question 1 5 points

What does EER stand for and what does it add to the basic ER model?

Enhanced Entity-Relationship; adds subclasses/superclasses, specialization/generalization, and categories Extended Entity-Relationship; adds only subclasses and superclasses Enhanced Entity-Relationship; adds only specialization hierarchies Extended Entity-Relationship; adds foreign key constraints

Question 2 5 points

Why do we need subclasses in database modeling?

To represent meaningful subgroupings of entities with specific attributes and relationships To reduce the size of the database To eliminate all redundancy To replace relationships between entities

Question 3 5 points

In the EMPLOYEE example, SECRETARY, ENGINEER, and TECHNICIAN are subclasses. What is the basis for this grouping?

Job type - the employee's specific job role Salary level Work location Years of experience

Question 4 5 points

What is attribute inheritance in the context of superclasses and subclasses?

Question 5 5 points

What are "subtypes" in EER modeling?

Another term for subclasses - meaningful subgroupings of a superclass entity type Different data types for attributes Types of relationships Weak entity types

Question 6 5 points

Give two examples of how EMPLOYEE entities could be meaningfully grouped into subclasses based on different criteria.

Question 7 5 points

A subclass entity is a member of which entity types?

Both the subclass AND its superclass Only the subclass Only the superclass Neither - it's independent

Question 8 5 points

What is specialization in EER modeling?

The process of defining a set of subclasses of an entity type (top-down approach) The process of combining multiple entity types into one (bottom-up approach) The process of creating relationships between entities The process of normalizing a database

Question 9 5 points

Explain the difference between specialization and generalization. Which is top-down and which is bottom-up?

Question 10 5 points

What is an "attribute-defined specialization" or "discriminator"?

A specialization where all subclasses have membership condition based on the same superclass attribute A specialization based on relationship types A specialization that doesn't use attributes A specialization that merges multiple superclasses

Question 11 5 points

In the EMPLOYEE example with SECRETARY, TECHNICIAN, and ENGINEER subclasses, what is the defining attribute (discriminator)?

Job_type Salary Name Department

Question 12 5 points

Describe generalization and explain why it is typically a "total" constraint.

Question 13 5 points

What is a specialization hierarchy?

A structure where every subclass has at most one superclass (single inheritance) A structure where subclasses can have multiple superclasses A ranking system for entities A tree structure of relationships

Question 14 5 points

What are the two main types of constraints that apply to specialization and generalization?

Disjointness constraint and Completeness (Exhaustiveness) constraint Primary key constraint and Foreign key constraint Existence constraint and Uniqueness constraint Cardinality constraint and Participation constraint

Question 15 5 points

What does the "disjointness constraint" specify and how is it represented in EER diagrams?

Question 16 5 points

What is an "overlapping" specialization?

A specialization where an entity can be a member of more than one subclass; represented by 'o' in EER diagrams A specialization where subclasses must be disjoint; represented by 'd' A specialization with duplicate attributes A specialization with shared relationships

Question 17 5 points

Explain the difference between "total" and "partial" completeness constraints in specialization.

Question 18 5 points

How is a "total" specialization represented in an EER diagram?

A double line connecting the superclass to the circle A single line connecting the superclass to the circle A dashed line A bold arrow

Question 19 5 points

What are the four possible combinations of disjointness and completeness constraints?

Question 20 5 points

What happens when you delete an entity from a superclass?

It is automatically deleted from all subclasses to which it belongs It remains in all subclasses Only the superclass data is deleted The deletion is not allowed

Question 21 5 points

When inserting an entity in a superclass of a TOTAL specialization, what must happen?

The entity must be inserted in at least one of the subclasses The entity cannot be inserted in any subclass The entity must be inserted in all subclasses The insertion is optional

Question 22 5 points

Explain what happens when inserting an entity in a superclass of a PARTIAL specialization.

Question 23 5 points

In an EER diagram, what does the symbol 'd' inside a circle represent?

Disjoint constraint - subclasses are disjoint (entity can be in at most one subclass) Derived attribute Delete constraint Discriminator attribute

Question 24 5 points

What is a "category" or "UNION type" in EER modeling?

A subclass that has several possible superclasses representing different entity types; a subset of the UNION of distinct entity types A superclass with multiple subclasses A type of relationship A specialization hierarchy

Question 25 5 points

How is attribute inheritance different in categories compared to regular specialization?

Question 26 5 points

Can the superclasses of a category have different key attributes?

Yes, superclasses may have different key attributes or the same key attribute No, they must always have the same key No, they cannot have any keys Only if they are weak entities

Question 27 5 points

Explain the difference between a "total category" and a "partial category".

Question 28 5 points

How is a total category represented in an EER diagram?

A double line connecting the category and the circle A single line connecting the category and the circle A dashed line No line at all

Question 29 5 points

When should you use categorization (UNION type) versus specialization/generalization?

Question 30 5 points

What are the three main EER concepts that improve the expressive power of ER diagrams?

Superclasses/subclasses (specialization/generalization), Categories (UNION types), and Aggregation Entities, Attributes, and Relationships Primary keys, Foreign keys, and Constraints Tables, Views, and Indexes

Chapter 3: Enhanced ER (EER) Model - Comprehensive Exam

📋 Exam Instructions

🔷 Section 1: EER Basics & Subclasses/Superclasses (7 questions)

🔺 Section 2: Specialization & Generalization (6 questions)

⚙️ Section 3: Constraints on Specialization/Generalization (10 questions)

🔶 Section 4: Categories (UNION Types) (7 questions)