Chapter 3 DB

Question 1

What is a relational database?

Answer 1

A relational database is a type of database that stores data in tables, which are structured in rows and columns.

Question 2

True or False: In a relational database, each table can have a unique primary key.

Answer 2

True

Question 3

What does SQL stand for?

Answer 3

Structured Query Language

Question 4

Fill in the blank: A __________ is a set of related data stored in a table.

Answer 4

relation

Question 5

Which of the following is NOT a characteristic of a relational database? (a) Data is organized in tables (b) Data is stored in files (c) Relationships are established using keys

Answer 5

b

Question 6

What is a primary key?

Answer 6

A primary key is a unique identifier for a record in a table.

Question 7

What is a foreign key?

Answer 7

A foreign key is a field in one table that uniquely identifies a row of another table.

Question 8

True or False: A relational database allows for data redundancy.

Answer 8

False

Question 9

What is normalization in the context of relational databases?

Answer 9

Normalization is the process of organizing data to minimize redundancy and improve data integrity.

Question 10

Fill in the blank: The process of combining data from multiple tables is known as __________.

Answer 10

joining

Question 11

What does the term ‘schema’ refer to in a relational database?

Answer 11

A schema is the structure that defines the organization of data, including tables, fields, and relationships.

Question 12

Which SQL command is used to retrieve data from a database?

Answer 12

SELECT

Question 13

What is a composite key?

Answer 13

A composite key is a combination of two or more columns in a table that can uniquely identify a record.

Question 14

True or False: A table can have multiple primary keys.

Answer 14

False

Question 15

What is the purpose of indexing in a relational database?

Answer 15

Indexing improves the speed of data retrieval operations on a database table.

Question 16

Fill in the blank: The __________ operation is used to add new records to a table.

Answer 16

INSERT

Question 17

What are constraints in a relational database?

Answer 17

Constraints are rules enforced on data columns to ensure data integrity.

Question 18

What SQL command is used to update existing records?

Answer 18

UPDATE

Question 19

True or False: A relational database can only store one type of data.

Answer 19

False

Question 20

What is the difference between a primary key and a unique key?

Answer 20

A primary key uniquely identifies a record and cannot contain null values, while a unique key also enforces uniqueness but can contain null values.

Question 21

What does the term ‘referential integrity’ mean?

Answer 21

Referential integrity ensures that relationships between tables remain consistent.

Question 22

Fill in the blank: The __________ clause is used to filter records in SQL.

Answer 22

WHERE

Question 23

What is a view in a relational database?

Answer 23

A view is a virtual table that is based on the result of a SELECT query.

Question 24

What SQL command is used to delete records from a table?

Answer 24

DELETE

Question 25

True or False: A relational database can be distributed across multiple servers.

Answer 25

True

Question 26

What is a transaction in the context of databases?

Answer 26

A transaction is a sequence of operations performed as a single logical unit of work.

Question 27

Fill in the blank: The __________ property ensures that a transaction is completed entirely or not at all.

Answer 27

atomicity

Question 28

What is the purpose of the GROUP BY clause in SQL?

Answer 28

The GROUP BY clause is used to arrange identical data into groups.

Question 29

What is a stored procedure?

Answer 29

A stored procedure is a set of SQL statements that can be stored and reused.

Question 30

True or False: Data in a relational database is inherently unstructured.

Answer 30

False

Question 31

What is the ACID property in the context of transactions?

Answer 31

ACID stands for Atomicity, Consistency, Isolation, and Durability, which are properties that guarantee reliable transaction processing.

Question 32

What is a database management system (DBMS)?

Answer 32

A DBMS is software that interacts with end users, applications, and the database itself to capture and analyze data.

Question 33

Fill in the blank: The __________ function is used to calculate the average value of a numeric column.

Answer 33

AVG

Question 34

What does the term 'denormalization' refer to?

Answer 34

Denormalization is the process of intentionally introducing redundancy into a database to improve performance.

Question 35

What is a data model?

Answer 35

A data model is a conceptual representation of data structures and their relationships.

Question 36

True or False: Relationships in a relational database can be one-to-one, one-to-many, or many-to-many.

Answer 36

True

Question 37

What is a data dictionary?

Answer 37

A data dictionary is a centralized repository of information about data, including definitions, relationships, and formats.

Question 38

Fill in the blank: The __________ function is used to count the number of rows in a table.

Answer 38

COUNT

Question 39

What is the purpose of the ORDER BY clause in SQL?

Answer 39

The ORDER BY clause is used to sort the result set of a query by one or more columns.

Question 40

What is the significance of the NULL value in a relational database?

Answer 40

NULL represents the absence of a value or an unknown value.

Question 41

True or False: In a relational database, a table can have multiple foreign keys.

Answer 41

True

Question 42

What does the term 'cardinality' refer to in the context of database relationships?

Answer 42

Cardinality refers to the uniqueness of data values contained in a particular column (attribute) of a database table.

Question 43

Fill in the blank: The __________ operation is used to combine rows from two or more tables based on a related column.

Answer 43

JOIN

Question 44

What is a trigger in a database?

Answer 44

A trigger is a set of instructions that are automatically executed in response to certain events on a particular table.

Question 45

What is the purpose of the HAVING clause in SQL?

Answer 45

The HAVING clause is used to filter records after a GROUP BY operation.