Computer Knowledge Questions & Answers

Q.11 Hard Database/SQL

What does BASE model in NoSQL stand for?

A Basically Available, Soft state, Eventually consistent

B Batch Available, System Events, Eventual consistency

C Buffer Availability, Strong consistency, Event-driven

D Backup Availability, Security-first, Efficient

Correct Answer: A. Basically Available, Soft state, Eventually consistent

EXPLANATION

BASE is an alternative to ACID, prioritizing availability and partition tolerance. It accepts temporary inconsistencies that resolve eventually (eventual consistency).

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Q.12 Hard Database/SQL

In cybersecurity, what is a zero-day vulnerability?

A A security flaw unknown to vendors with no patch available

B A vulnerability found on the first day of software release

C A virus that activates at midnight

D A type of brute-force attack

Correct Answer: A. A security flaw unknown to vendors with no patch available

EXPLANATION

Zero-day vulnerabilities are previously unknown exploits with no patch. They're extremely dangerous because users have no defense until vendors develop and release fixes.

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Q.13 Hard Database/SQL

What does CAP theorem state in distributed systems?

A A system can guarantee at most 2 of 3: Consistency, Availability, Partition tolerance

B All distributed systems must be Consistent, Available, and Partition-tolerant

C Consistency requires Availability and Partitions

D Availability is always achieved in partitioned systems

Correct Answer: A. A system can guarantee at most 2 of 3: Consistency, Availability, Partition tolerance

EXPLANATION

CAP theorem (Brewer's theorem) states distributed systems must choose 2 of 3 properties: strong consistency (C), continuous availability (A), or tolerance to network partitions (P).

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Q.14 Hard Database/SQL

In the context of graph databases, what is the primary advantage over relational databases for relationship-heavy queries?

A Lower storage requirements

B Faster execution of complex relationship traversals

C Better support for unstructured data

D Superior ACID compliance

Correct Answer: B. Faster execution of complex relationship traversals

EXPLANATION

Graph databases excel at querying relationships with O(1) traversal time, whereas relational databases require expensive JOIN operations for similar queries.

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Q.15 Hard Database/SQL

What is the primary vulnerability addressed by SQL injection prevention techniques like parameterized queries?

A Buffer overflow attacks

B Injection of malicious SQL code into database queries

C Man-in-the-middle attacks

D DDoS attacks on database server

Correct Answer: B. Injection of malicious SQL code into database queries

EXPLANATION

Parameterized queries prevent SQL injection by separating query structure from data, ensuring user input cannot be interpreted as executable code.

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Q.16 Hard Database/SQL

In network protocols, which layer does TCP/IP operate at?

A Physical Layer

B Data Link Layer

C Transport and Network Layers

D Application Layer only

Correct Answer: C. Transport and Network Layers

EXPLANATION

TCP operates at Layer 4 (Transport) and IP at Layer 3 (Network) in the OSI model. Together they form the TCP/IP protocol suite.

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Q.17 Hard Database/SQL

Which of the following best describes eventual consistency in distributed databases?

A All nodes have identical data at all times

B Data will be consistent across all nodes eventually, not immediately

C Data consistency is never achieved

D Only primary nodes maintain consistency

Correct Answer: B. Data will be consistent across all nodes eventually, not immediately

EXPLANATION

Eventual consistency is a model in NoSQL and distributed systems where updates propagate asynchronously, achieving consistency over time rather than immediately.

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Q.18 Hard Database/SQL

What is a deadlock in database management?

A A situation where transactions block indefinitely waiting for each other

B Loss of database connection

C Unauthorized access to database

D Corruption of data files

Correct Answer: A. A situation where transactions block indefinitely waiting for each other

EXPLANATION

A deadlock occurs when two or more transactions wait for resources held by each other, creating a circular wait condition that prevents progress.

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Q.19 Hard C Programming

What is the output of this code involving bitwise operations?
int x = 5; // binary: 0101
int y = 3; // binary: 0011
printf("%d", x ^ y); // XOR operation

A 6

B 7

C 1

D 8

Correct Answer: A. 6

EXPLANATION

XOR operation: 5 ^ 3. Binary: 0101 ^ 0011 = 0110 = 6. XOR returns 1 when bits are different, 0 when same.

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Q.20 Hard C Programming

What is the output of this recursive function?
int func(int n) {
if(n

A 10

B 24

C 12

D 4

Correct Answer: B. 24

EXPLANATION

This function calculates factorial. func(4) = 4 * func(3) = 4 * (3 * func(2)) = 4 * (3 * (2 * func(1))) = 4 * 3 * 2 * 1 = 24.

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