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

A.

Object-Relational Database Management System (ORDBMS)

B.

Network Database

C.

Flat File Database

D.

Hierarchical Database

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

A.

Optimistic Locking

B.

Two-Phase Locking

C.

Table Locking

D.

MVCC (Multi-Version Concurrency Control)

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

A.

1521

B.

3306

C.

5432

D.

8080

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

A.

pg_terminal

B.

psql

C.

sqlcmd

D.

pgAdmin

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

A.

config.json

B.

postgresql.conf

C.

pg_hba.conf

D.

pg_ident.conf

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

A.

postgres

B.

sa

C.

admin

D.

root

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

A.

\l

B.

SHOW DATABASES;

C.

Both A and B

D.

\list

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

A.

TEXT

B.

JSON

C.

JSONB

D.

VARCHAR

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

A.

INIT DATABASE name;

B.

NEW DATABASE name;

C.

MAKE DATABASE name;

D.

CREATE DATABASE name;

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

A.

Wide-Area Latency

B.

Write-Ahead Logging

C.

Write-After Log

D.

Web Application Layer

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

A.

\connect dbname

B.

\c dbname

C.

Both A and B

D.

\use dbname

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

A.

ERASE TABLE

B.

REMOVE TABLE

C.

DROP TABLE

D.

DELETE TABLE

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

A.

SERIAL

B.

AUTO_INT

C.

INT

D.

NUMERIC

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

A.

To drop the table structure

B.

To delete all rows quickly without logging individual row deletions

C.

To delete specific rows based on a condition

D.

To minify the database size

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

A.

UNIQUE

B.

NOT NULL

C.

CHECK

D.

PRIMARY KEY

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

A.

RENAME TABLE users TO customers;

B.

MODIFY TABLE users RENAME customers;

C.

ALTER TABLE users RENAME TO customers;

D.

UPDATE TABLE users SET NAME = customers;

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

A.

=

B.

LIKE

C.

SAME

D.

MATCH

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

A.

A NULL value

B.

A numeric digit

C.

Exactly one character

D.

Zero or more characters

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

A.

HAVING

B.

GROUP BY

C.

WHERE

D.

ORDER BY

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

A.

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

B.

UPDATE students ADD (1, 'John');

C.

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

D.

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

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

A.

SELECT * FROM employees;

B.

GET * FROM employees;

C.

SELECT ALL FROM employees;

D.

FETCH employees;

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

A.

TOP

B.

LIMIT

C.

STOP

D.

ROWNUM

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

A.

JUMP

B.

NEXT

C.

SKIP

D.

OFFSET

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.

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

C.

CHANGE 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 table structure.

B.

It throws a syntax error.

C.

It deletes the first row.

D.

It deletes all rows in the table.

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

A.

RETURN

B.

RETURNING

C.

OUTPUT

D.

BACK

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

A.

DATETIME

B.

DATE

C.

TIME

D.

TIMESTAMP

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

A.

MODIFY TABLE

B.

ALTER TABLE

C.

UPDATE TABLE

D.

CHANGE TABLE

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

A.

DISTINCT

B.

PRIMARY

C.

UNIQUE

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.

SORT BY column_name DESC

B.

ORDER BY column_name ASC

C.

ORDER BY column_name DESC

D.

GROUP BY column_name DESC

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

A.

ADD()

B.

TOTAL()

C.

COUNT()

D.

SUM()

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.

ALTER TABLE people ADD COLUMN age INTEGER;

C.

ALTER people ADD age INTEGER;

D.

INSERT COLUMN age INTEGER INTO people;

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

A.

Describes the table structure

B.

Duplicates the table

C.

Downloads the table

D.

Deletes 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.

XOR

C.

OR

D.

AND

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

A.

EQUALS NULL

B.

= NULL

C.

== NULL

D.

IS NULL

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

A.

phpMyAdmin

B.

Workbench

C.

Compass

D.

pgAdmin

39 $What does the PRIMARY KEY constraint imply?$

A.

Both UNIQUE and NOT NULL

B.

UNIQUE only

C.

NOT NULL only

D.

Just an index

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.

HAVING

B.

FILTER

C.

WHERE

D.

LIMIT

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

A.

REMOVE DATABASE name;

B.

DROP DATABASE name;

C.

TRUNCATE DATABASE name;

D.

DELETE DATABASE name;

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

A.

To specify multiple possible values for a column

B.

To check for NULL

C.

To specify a range

D.

To search text patterns

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

A.

INT

B.

BOOLEAN

C.

BINARY

D.

VARCHAR(1)

45 $What does the BETWEEN operator select?$

A.

Values that match a list

B.

Values that are distinct

C.

Values within a given range

D.

Values that are null

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 ... DELETE COLUMN ...

B.

ALTER TABLE ... DROP COLUMN ...

C.

DROP COLUMN ... FROM ...

D.

ALTER TABLE ... REMOVE COLUMN ...

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

A.

UPDATE

B.

CREATE

C.

INSERT

D.

SELECT

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

A.

Descending

B.

Random

C.

Insertion Order

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