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Question 1 of 60 Quiz ID: q1

According to the learning outcomes, which of the following is NOT a stated goal for students after completing the module?

Explain the role of database systems in information management.

Design and implement a distributed NoSQL database cluster.

Apply entity-relationship modelling for simple database requirements.

Demonstrate the use of a query language to create, update and query a simple database.

Question 2 of 60 Quiz ID: q2

What is the largest component of the final grade, as per the grading scheme?

Mini project (Group)

Mid Term Quiz (Moodle)

2-hour closed book examination

In-class/lab pop quizzes/labs

Question 3 of 60 Quiz ID: q3

A Database Management System (DBMS) is best described as:

A collection of interrelated data and programs to access that data, providing a convenient and efficient environment.

A single, large file containing all of an enterprise's information in a sequential format.

A programming language specifically designed for statistical analysis.

A hardware component used for increasing the processing speed of a server.

Question 4 of 60 Quiz ID: q4

Which of the following is cited as a major drawback of using file systems instead of a DBMS to store data?

Excessive data normalization leading to inefficiency.

Automatic enforcement of complex integrity constraints.

Data redundancy and inconsistency due to multiple file formats and duplication.

Built-in, robust mechanisms for handling concurrent user updates.

Question 5 of 60 Quiz ID: q5

The 'Atomicity of updates' problem in file systems refers to:

The inability to store data in small, indivisible units.

The risk that a system failure may leave the database in an inconsistent state with only partial updates completed.

The challenge of allowing multiple users to access data at the same time.

The difficulty in representing relationships between different data elements.

Question 6 of 60 Quiz ID: q6

Which level of abstraction describes how a record (e.g., a customer) is physically stored on disk?

View Level

Application Level

Logical Level

Physical Level

Question 7 of 60 Quiz ID: q7

In the three-level architecture, the 'View Level' is primarily used for:

Describing the physical storage structure of the entire database.

Defining the logical structure of all data and relationships.

Hiding certain data (like salary) from users for security purposes and providing application-specific data perspectives.

Optimizing query execution plans for faster performance.

Question 8 of 60 Quiz ID: q8

In database terminology, the logical structure of the database (e.g., tables, attributes, relationships) is known as the:

Instance

Schema

Domain

Abstraction

Question 9 of 60 Quiz ID: q9

The actual content of the database at a specific point in time is called the:

Schema

Instance

Catalog

Model

Question 10 of 60 Quiz ID: q10

Physical Data Independence is a crucial concept that allows us to:

Change the logical schema without affecting application programs.

Change the physical schema (e.g., storage structures, indexes) without changing the logical schema.

Change the view definitions without affecting the physical storage.

Change the database instance without affecting the schema.

Question 11 of 60 Quiz ID: q11

Which of the following is a tool for describing data, data relationships, data semantics, and data constraints?

A Data Dictionary

A Data Model

A Storage Manager

A Query Optimizer

Question 12 of 60 Quiz ID: q12

Which data model uses a collection of tables to represent both data and the relationships among that data?

Entity-Relationship Model

Object-Oriented Model

Relational Model

Hierarchical Model

Question 13 of 60 Quiz ID: q13

A language for accessing and manipulating the data organized by a data model is known as a:

Data Definition Language (DDL)

Data Manipulation Language (DML)

Data Control Language (DCL)

Storage Description Language (SDL)

Question 14 of 60 Quiz ID: q14

In a DML, a __________ language requires the user to specify what data is needed and how to get it, while a __________ language only requires specifying what data is needed.

Declarative, Procedural

Procedural, Declarative

Functional, Imperative

Imperative, Functional

Question 15 of 60 Quiz ID: q15

The SQL command 'CREATE TABLE' is a primary example of a:

Data Manipulation Language (DML) statement.

Data Definition Language (DDL) statement.

Data Control Language (DCL) statement.

Transaction Control Language (TCL) statement.

Question 16 of 60 Quiz ID: q16

Metadata, which is 'data about data', is stored in the:

Database Instance

Data Dictionary / System Catalog

Query Evaluation Engine

Buffer Manager

Question 17 of 60 Quiz ID: q17

The constraint that 'the dept_name value in any instructor tuple must appear in the department relation' is an example of:

Entity Integrity

Domain Constraint

Referential Integrity

Authorization

Question 18 of 60 Quiz ID: q18

The process of deciding on the database schema (what attributes to record, how to distribute them among relations) is part of:

Physical Design

Logical Design

View Design

Transaction Design

Question 19 of 60 Quiz ID: q19

Looking at the combined 'univ' table on page 20, what is the primary design flaw it demonstrates?

It uses inefficient data types for the attributes.

It lacks a primary key, violating entity integrity.

It combines instructor and department data, leading to data redundancy (e.g., repeated department info) and potential anomalies.

The attribute names are not descriptive enough.

Question 20 of 60 Quiz ID: q20

__________ Theory formalizes what database designs are 'bad' and provides tests to identify them.

Entity-Relationship

Normalization

Transaction

Concurrency Control

Question 21 of 60 Quiz ID: q21

In the Entity-Relationship model, an association among several entities is called a:

Attribute

Entity

Relationship

Schema

Question 22 of 60 Quiz ID: q22

Object-Relational Data Models extend the relational model by:

Replacing tables with object hierarchies.

Including object orientation and allowing attributes to have complex, non-atomic types.

Removing the need for a declarative query language like SQL.

Eliminating the concepts of primary and foreign keys.

Question 23 of 60 Quiz ID: q23

Which program module provides the interface between the low-level data stored in the database and the application programs/queries?

Query Optimizer

Transaction Manager

Storage Manager

DML Compiler

Question 24 of 60 Quiz ID: q24

Which of the following is a responsibility of the Storage Manager?

Parsing and translating SQL queries.

Ensuring the atomicity of transactions.

Managing file organization, indexing, and hashing.

Optimizing relational algebra expressions.

Question 25 of 60 Quiz ID: q25

The three main steps in query processing are:

Parsing, Authorization, Evaluation

Parsing and translation, Optimization, Evaluation

Indexing, Hashing, Retrieval

Compilation, Linking, Execution

Question 26 of 60 Quiz ID: q26

The query optimizer's goal is to:

Translate a SQL query into a relational algebra expression.

Choose the most efficient evaluation plan for a query from a set of alternatives.

Execute the low-level instructions of a query plan.

Check the user's authorization to run the query.

Question 27 of 60 Quiz ID: q27

A collection of operations that performs a single logical function in a database application is called a:

Query

Program

Transaction

Schema

Question 28 of 60 Quiz ID: q28

The component that ensures the database remains in a consistent state despite system failures is the:

Storage Manager

Query Processor

Transaction-Management Component

Buffer Manager

Question 29 of 60 Quiz ID: q29

The component that controls the interaction among concurrent transactions to ensure consistency is the:

Authorization Manager

Concurrency-Control Manager

File Manager

Integrity Manager

Question 30 of 60 Quiz ID: q30

In the database system architecture diagram, which users 'write application programs'?

Naive Users

Application Programmers

Sophisticated Users

Database Administrators

Question 31 of 60 Quiz ID: q31

Which user type is responsible for overall control of the database system and its use?

Naive Users

Application Programmers

Sophisticated Users

Database Administrators

Question 32 of 60 Quiz ID: q32

The shift from sequential tape storage to direct access via hard disks in the late 1960s/70s enabled the development of:

Punched card input systems.

High-performance transaction processing systems.

Web commerce applications.

XML data interchange standards.

Question 33 of 60 Quiz ID: q33

The set of allowed values for a particular attribute is called its:

Schema

Instance

Domain

Tuple

Question 34 of 60 Quiz ID: q34

In the relational model, attribute values are normally required to be:

Composite

Atomic

Null

Derived

Question 35 of 60 Quiz ID: q35

A subset of the Cartesian product of a list of domains defines a:

Schema

Relation

Key

View

Question 36 of 60 Quiz ID: q36

Why is the order of tuples irrelevant in a relation?

Because it makes data entry faster.

Because it simplifies the physical storage mechanism.

Because relations are defined as sets of tuples, and sets are unordered by definition.

Because SQL does not have a command to reorder tuples.

Question 37 of 60 Quiz ID: q37

Breaking up information about an enterprise into multiple relations (e.g., instructor, department) instead of one big table helps avoid:

The use of SQL.

Data isolation.

Repetition of information and the need for null values.

The need for a storage manager.

Question 38 of 60 Quiz ID: q38

A __________ is a set of attributes that uniquely identifies a tuple within a relation.

Superkey

Domain

Schema

View

Question 39 of 60 Quiz ID: q39

If {ID} and {ID, name} are both superkeys for the instructor relation, which one is the candidate key?

{ID}

{ID, name}

Both are candidate keys.

Neither is a candidate key; a candidate key must include only one attribute.

Question 40 of 60 Quiz ID: q40

A foreign key in one relation must correspond to either the primary key or a candidate key of another relation. This rule enforces:

Entity Integrity

Domain Integrity

Referential Integrity

Authorization

Question 41 of 60 Quiz ID: q41

In the bank schema (Page 46), the 'branch-name' attribute in the 'account' relation is a __________, referencing the __________ relation.

Primary Key, loan

Foreign Key, branch

Candidate Key, depositor

Superkey, customer

Question 42 of 60 Quiz ID: q42

From the university database instance (Page 49), which of the following INSERT operations would violate referential integrity?

Inserting a new instructor with ID='12345', name='Smith', dept_name='Physics', salary=80000.

Inserting a new instructor with ID='99999', name='Jones', dept_name='Astrology', salary=50000.

Inserting a new department with dept_name='Linguistics', building='Watson', budget=40000.

Deleting the department 'History'.

Question 43 of 60 Quiz ID: q43

From the same instance (Page 49), which DELETE operation could potentially violate referential integrity?

Deleting instructor 'Mozart' (ID 15151).

Deleting the 'Physics' department.

Deleting instructor 'Singh' (ID 76543).

Deleting the 'Music' department.

Question 44 of 60 Quiz ID: q44

Even though no two instructors in the current instance (Page 50) have the same name, why is 'name' a poor choice for a primary key?

Because it is not a minimal superkey.

Because the domain of 'name' is not atomic.

Because it cannot enforce referential integrity.

Because the schema does not allow it. The primary key must be 'ID'.

Question 45 of 60 Quiz ID: q45

Which category of 'pure' relational query languages is considered procedural?

Tuple Relational Calculus

Domain Relational Calculus

Relational Algebra

Structured Query Language (SQL)

Question 46 of 60 Quiz ID: q46

The σ (sigma) operator in relational algebra is used for:

Selecting columns (attributes).

Selecting tuples (rows) that satisfy a given predicate.

Combining two relations through a Cartesian product.

Renaming attributes or relations.

Question 47 of 60 Quiz ID: q47

The Π (pi) operator in relational algebra is used for:

Selecting columns (attributes).

Selecting tuples (rows) that satisfy a given predicate.

Combining two relations through a Cartesian product.

Renaming attributes or relations.

Question 48 of 60 Quiz ID: q48

The operation that returns all tuples that are in either of two relations, eliminating duplicates, is the:

Set Difference (-)

Cartesian Product (×)

Union (∪)

Natural Join (⋈)

Question 49 of 60 Quiz ID: q49

The operation that returns all tuples that are in one relation but not in another is the:

Set Difference (-)

Cartesian Product (×)

Union (∪)

Natural Join (⋈)

Question 50 of 60 Quiz ID: q50

The most general type of join, which pairs every tuple in one relation with every tuple in another, is the:

Natural Join (⋈)

Theta Join

Equijoin

Cartesian Product (×)

Question 51 of 60 Quiz ID: q51

The Natural Join operation:

Requires the user to specify the join condition explicitly.

Is performed on all attributes with the same name in the two relations.

Always results in a relation with more attributes than either of the input relations.

Cannot be used if the two relations have no attributes in common.

Question 52 of 60 Quiz ID: q52

Given the bank schema, which relational algebra expression finds names of all branches in 'Chicago'?

Π branch-name (σ branch-city='Chicago' (branch))

σ branch-city='Chicago' (Π branch-name (branch))

Π branch-name (branch) ∪ Π branch-city (branch)

σ branch-city='Chicago' (account)

Question 53 of 60 Quiz ID: q53

Given the bank schema, which expression finds names of all borrowers with a loan in the 'Downtown' branch?

Π customer-name (σ branch-name='Downtown' (borrower))

Π customer-name (σ branch-name='Downtown' (borrower ⋈ loan))

Π customer-name (σ branch-name='Downtown' (loan))

Π customer-name (borrower) ∩ Π customer-name (σ branch-name='Downtown' (loan))

Question 54 of 60 Quiz ID: q54

For the Employee/Assignment/Project schema (Ex 1.7), which expression lists names and budgets of projects started before May 1, 2008?

Π proj_name, budget (σ proj_start_date < '2008-05-01' (Project))

σ proj_start_date < '2008-05-01' (Π proj_name, budget (Project))

Π proj_name, budget (Project ⋈ Assignment)

Π emp_name (σ proj_start_date < '2008-05-01' (Project))

Question 55 of 60 Quiz ID: q55

Which expression finds names of employees from 'Moratuwa' who work on projects also located in 'Moratuwa'?

Π emp_name (σ emp_city='Moratuwa' (Employee))

Π emp_name (σ proj_location='Moratuwa' (Project))

Π emp_name ( σ emp_city='Moratuwa' (Employee) ⋈ Assignment ⋈ σ proj_location='Moratuwa' (Project) )

Π emp_name (Employee) ∩ Π emp_name (σ proj_location='Moratuwa' (Project))

Question 56 of 60 Quiz ID: q56

The result of a relational algebra expression is always a:

Number

Relation

List of attribute names

Single data value

Question 57 of 60 Quiz ID: q57

In the context of the history of database systems, what was the significance of hard disks replacing magnetic tapes?

They made data sequential access faster.

They enabled direct access to data, which was crucial for interactive database systems and transaction processing.

They simplified the network and hierarchical data models.

They were the storage medium for the first relational prototypes.

Question 58 of 60 Quiz ID: q58

The emergence of Web commerce in the 1990s placed new demands on databases, including:

The need to process transactions sequentially.

The need to handle very high volumes of read and write operations from a global user base.

A decreased need for transaction management.

The elimination of the client-server architecture.

Question 59 of 60 Quiz ID: q59

The rise of semi-structured data formats like XML in the 2000s led to databases that:

Strictly enforced the atomicity requirement of the relational model.

Abandoned the concept of a schema entirely.

Could store and query data that did not fit neatly into rigid, predefined tables.

Were exclusively used for online transaction processing (OLTP).

Question 60 of 60 Quiz ID: q60

Comparing the centralized and client-server database architectures, a key advantage of client-server is:

Simpler hardware requirements for the server.

Reduced network traffic, as all processing is done on one machine.

The ability to offload user interface and application logic to client machines, improving scalability.

The elimination of the need for a query language like SQL.

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