1 $What type of database management system is PostgreSQL classified as?$

A.

Flat File Database

B.

Hierarchical Database

C.

Network Database

D.

Object-Relational Database Management System (ORDBMS)

2 $Which mechanism does PostgreSQL use to handle concurrency without read locks blocking write locks?$

A.

Table Locking

B.

MVCC (Multi-Version Concurrency Control)

C.

Two-Phase Locking

D.

Optimistic Locking

3 $What is the default TCP port that PostgreSQL listens on?$

A.

3306

B.

5432

C.

1521

D.

8080

4 $What is the name of the interactive terminal-based command-line tool for PostgreSQL?$

A.

sqlcmd

B.

pgAdmin

C.

psql

D.

pg_terminal

5 $Which configuration file is primarily responsible for controlling client authentication in PostgreSQL?$

A.

pg_hba.conf

B.

config.json

C.

pg_ident.conf

D.

postgresql.conf

6 $What is the default superuser account created during PostgreSQL installation?$

A.

sa

B.

admin

C.

root

D.

postgres

7 $Which command inside the psql interface is used to list all databases?$

A.

\list

B.

SHOW DATABASES;

C.

Both A and B

D.

\l

8 $Which data type in PostgreSQL is best suited for storing JSON data with indexing capabilities?$

A.

VARCHAR

B.

JSON

C.

JSONB

D.

TEXT

9 $Which SQL statement is used to create a new database in PostgreSQL?$

A.

CREATE DATABASE name;

B.

INIT DATABASE name;

C.

NEW DATABASE name;

D.

MAKE DATABASE name;

10 $What does the acronym WAL stand for in the context of PostgreSQL architecture?$

A.

Web Application Layer

B.

Wide-Area Latency

C.

Write-After Log

D.

Write-Ahead Logging

11 $Which command allows you to connect to a specific database from within the psql prompt?$

A.

\c dbname

B.

\use dbname

C.

Both A and B

D.

\connect dbname

12 $To remove a table and all its data from the database, which command is used?$

A.

DROP TABLE

B.

ERASE TABLE

C.

DELETE TABLE

D.

REMOVE TABLE

13 $Which PostgreSQL data type is an auto-incrementing integer typically used for primary keys?$

A.

INT

B.

NUMERIC

C.

SERIAL

D.

AUTO_INT

14 $What is the purpose of the 'TRUNCATE' command?$

A.

To minify the database size

B.

To delete specific rows based on a condition

C.

To drop the table structure

D.

To delete all rows quickly without logging individual row deletions

15 $Which constraint ensures that a column cannot contain NULL values?$

A.

UNIQUE

B.

PRIMARY KEY

C.

NOT NULL

D.

CHECK

16 $How do you rename an existing table 'users' to 'customers' in PostgreSQL?$

A.

MODIFY TABLE users RENAME customers;

B.

ALTER TABLE users RENAME TO customers;

C.

RENAME TABLE users TO customers;

D.

UPDATE TABLE users SET NAME = customers;

17 $Which operator is used for pattern matching with wildcards in a WHERE clause?$

A.

MATCH

B.

SAME

C.

LIKE

D.

=

18 $In the context of the LIKE operator, what does the '%' wildcard represent?$

A.

Zero or more characters

B.

A NULL value

C.

Exactly one character

D.

A numeric digit

19 $Which SQL clause is used to filter records that meet a specified condition?$

A.

GROUP BY

B.

HAVING

C.

ORDER BY

D.

WHERE

20 $What is the correct syntax to insert a new record into the 'students' table?$

A.

UPDATE students ADD (1, 'John');

B.

INSERT INTO students (id, name) VALUES (1, 'John');

C.

ADD TO students VALUES (1, 'John');

D.

INSERT students SET id=1, name='John';

21 $How can you retrieve all columns from the 'employees' table?$

A.

SELECT ALL FROM employees;

B.

SELECT * FROM employees;

C.

GET * FROM employees;

D.

FETCH employees;

22 $Which clause allows you to limit the number of rows returned by a query?$

A.

TOP

B.

STOP

C.

ROWNUM

D.

LIMIT

23 $Which command allows you to skip a specific number of rows before returning the result set?$

A.

OFFSET

B.

NEXT

C.

JUMP

D.

SKIP

24 $What is the correct syntax to update the email of a user with id 5?$

A.

MODIFY users SET email = 'new@test.com' WHERE id = 5;

B.

CHANGE users email = 'new@test.com' WHERE id = 5;

C.

SET users.email = 'new@test.com' WHERE id = 5;

D.

UPDATE users SET email = 'new@test.com' WHERE id = 5;

25 $What happens if you run a DELETE FROM table_name command without a WHERE clause?$

A.

It deletes the first row.

B.

It deletes all rows in the table.

C.

It deletes the table structure.

D.

It throws a syntax error.

26 $Which keyword is used to return data immediately after an INSERT, UPDATE, or DELETE operation in PostgreSQL?$

A.

OUTPUT

B.

RETURNING

C.

RETURN

D.

BACK

27 $Which PostgreSQL data type stores both date and time?$

A.

TIME

B.

DATE

C.

TIMESTAMP

D.

DATETIME

28 $Which command is used to modify the structure of an existing table, such as adding a column?$

A.

ALTER TABLE

B.

UPDATE TABLE

C.

CHANGE TABLE

D.

MODIFY TABLE

29 $To ensure a column's value is unique across the entire table, which constraint should be used?$

A.

PRIMARY

B.

UNIQUE

C.

DISTINCT

D.

SINGLE

30 $Which operator is used to combine string values in PostgreSQL?$

A.

||

B.

CONCAT()

C.

+

D.

&

31 $How do you sort the result set in descending order?$

A.

ORDER BY column_name ASC

B.

GROUP BY column_name DESC

C.

SORT BY column_name DESC

D.

ORDER BY column_name DESC

32 $Which function is used to count the number of rows in a selection?$

A.

COUNT()

B.

TOTAL()

C.

SUM()

D.

ADD()

33 $What is the purpose of the DISTINCT keyword in a SELECT statement?$

A.

To sort results

B.

To filter null values

C.

To limit results

D.

To remove duplicate values from the result set

34 $Which of the following is a correct command to add a new column 'age' of type integer to table 'people'?$

A.

UPDATE TABLE people ADD age INTEGER;

B.

INSERT COLUMN age INTEGER INTO people;

C.

ALTER people ADD age INTEGER;

D.

ALTER TABLE people ADD COLUMN age INTEGER;

35 $What does the psql command '\d table_name' do?$

A.

Describes the table structure

B.

Duplicates the table

C.

Deletes the table

D.

Downloads the table

36 $Which logical operator is used to display a record if any of the conditions separated by it are true?$

A.

NOT

B.

AND

C.

OR

D.

XOR

37 $How do you check for a NULL value in a WHERE clause?$

A.

EQUALS NULL

B.

IS NULL

C.

== NULL

D.

= NULL

38 $Which PostgreSQL tool is a popular open-source GUI for database management?$

A.

Compass

B.

pgAdmin

C.

phpMyAdmin

D.

Workbench

39 $What does the PRIMARY KEY constraint imply?$

A.

Both UNIQUE and NOT NULL

B.

NOT NULL only

C.

Just an index

D.

UNIQUE only

40 $Which command allows you to quit the psql terminal?$

A.

exit

B.

\q

C.

quit

D.

logout

41 $Which clause is used to filter groups of rows created by GROUP BY?$

A.

LIMIT

B.

HAVING

C.

WHERE

D.

FILTER

42 $Which statement is used to delete an entire database?$

A.

REMOVE DATABASE name;

B.

TRUNCATE DATABASE name;

C.

DELETE DATABASE name;

D.

DROP DATABASE name;

43 $What is the purpose of the 'IN' operator?$

A.

To check for NULL

B.

To search text patterns

C.

To specify a range

D.

To specify multiple possible values for a column

44 $Which data type would be most appropriate for a True/False value?$

A.

VARCHAR(1)

B.

INT

C.

BOOLEAN

D.

BINARY

45 $What does the BETWEEN operator select?$

A.

Values that match a list

B.

Values that are distinct

C.

Values that are null

D.

Values within a given range

46 $To create a foreign key, which table is modified?$

A.

Both tables

B.

The system table

C.

The child table

D.

The parent table

47 $Which command is used to remove a specific column from a table?$

A.

ALTER TABLE ... REMOVE COLUMN ...

B.

DROP COLUMN ... FROM ...

C.

ALTER TABLE ... DELETE COLUMN ...

D.

ALTER TABLE ... DROP COLUMN ...

48 $Which basic SQL command is NOT part of CRUD operations?$

A.

CREATE

B.

SELECT

C.

UPDATE

D.

INSERT

49 $What is the default sort order if ASC or DESC is not specified in ORDER BY?$

A.

Random

B.

Insertion Order

C.

Descending

D.

Ascending

50 $Which character is used to denote a parameter/variable placeholder in a prepared statement in psql (e.g., $1, $2)?$

A.

?

B.

:

C.

$

D.

@

Unit 5 - Practice Quiz