Sample Quiz

A collection of concepts that can be used to describe the structure of a database

The data in the database at a particular moment in time

The capacity to change the internal schema without having to change the conceptual schema

The capacity to change the conceptual schema without having to change external schemas or application programs

A database software component that concerns with the rearrangement and possible reordering of operations, elimination of redundancies, and use of efficient search algorithms during execution

A state that satisfies the structure and constraints specified in the database schema

Which of the following is a conceptual data model used in database design?

Which of the following statements are false to good database design principles?

Which of the following is an example of an improper minimal key in an Entity-Relationship (ER) model?

Why do we need a weak entity type in an Entity-Relationship (ER) model?

A DBMS should provide security protection against hardware or software malfunction as a critical function to the users.

An attribute that exists in several entity types may be elevated or promoted to an independent entity type.

The schema of a database often changes frequently to represent the users' requirements.

A database always starts out in an empty state when it’s first created.

A complicated attribute is an attribute type in ER modeling.

The three-tier client-server architecture is commonly adopted by a web application that has a database component.

A DBMS always rely on the computer OS to schedule disk read/write operations.

A document-based data model is a form of a NOSQL system.

Derived attributes are always stored permanently in a DBMS.

Relationship types are not allowed to have local attributes.

Which of the following data types is NOT typically supported by a DBMS?

Which of the following statements regarding Conceptual Data Model, Logical/Implementational Data Model, and Physical Data Model are FALSE? Select all that apply.

In the ER model, when an entity type does not have key attributes of its own and cannot be identified without an owner entity, it is referred to as a:

Given the following entity type ClassRegistration, which of the following are valid minimal key candidates for uniquely identifying each entity in the set. Select all that apply.

Entity: ClassRegistration

Attributes:

RegistrationID (unique for each registration) StudentID (unique for each student) CourseID (unique for each course) Semester RegistrationDate

In the ER model, when an attribute of one entity refers to another entity type, it should be represented as a relationship rather than an attribute.

If the subclasses of a superclass are disjoint, what does it mean?

Which of the following is true about a subclass/superclass in an ER diagram?

Which of the following is NOT a concept introduced in the EER model?

Suppose we have a superclasss entity called "Vehicle" with attributes "Make", "Model", "Year", and "VIN". It is appropriate for it to also have a subclass entity called "Car" with attributes "Number of Doors" and "Color".

Suppose we have a superclasss entity called "Vehicle" with attributes "Make", "Model", "Year", and "VIN". It is appropriate for it to also have another subclass entity called "Driver" with attributes "Name", "Age", and "License Number". This is because we want to represent which drivers are authorized to drive which vehicles.

In the context of Relational Model, a domain is a set of atomic values, which means that each value in the domain is indivisible.

The following relation schema has a degree (or arity) of 8:

STUDENT(Ssn, Name, Home_phone, Address, Office_phone, Age, Gpa)

Each unique attribute in the same relation R must have different data types and domains.

If two tuples have NULL values for an attribute (e.g. Address), then they are still comparable.

What is the purpose of the entity integrity constraint/primary key constraint in a relational database?

Select all the statements that are true from the following:

Which of the following is NOT a valid approach for mapping an EER superclass/subclass structure to a relational model?

What is a drawback of using the Single Table approach?

If a relation R(A, B, C, D) has 100 rows and you apply σ(A = 'X')(R), which of the following is true?

If a relation R(A, B, C, D) has 100 rows and you apply π(A, C)(R), which of the following is true?

What is a similarity between Selection (σ) and Projection (π)?