Showing 121–130 of 150 questions
Q.121
Medium
Database/SQL
Which of the following is NOT a characteristic of relational databases?
A
ACID compliance
B
Flexible schema
C
Structured data storage
D
Data integrity constraints
Correct Answer:
B. Flexible schema
Explanation:
Relational databases have fixed schemas. Flexible schemas are a characteristic of NoSQL databases like MongoDB.
Q.122
Medium
Database/SQL
What does CAP theorem state about distributed database systems?
A
All three properties can be achieved simultaneously
B
Only two of Consistency, Availability, and Partition tolerance can be guaranteed
C
Consistency is always sacrificed first
D
Partition tolerance is optional in modern systems
Correct Answer:
B. Only two of Consistency, Availability, and Partition tolerance can be guaranteed
Explanation:
CAP theorem proves that distributed systems can guarantee at most 2 of 3 properties: Consistency, Availability, and Partition tolerance.
Q.123
Medium
Database/SQL
In SQL, what is the difference between HAVING and WHERE clauses?
A
Both serve identical purposes
B
WHERE filters rows before grouping; HAVING filters groups after aggregation
C
HAVING is used for individual row filtering
D
WHERE can only be used with JOIN operations
Correct Answer:
B. WHERE filters rows before grouping; HAVING filters groups after aggregation
Explanation:
WHERE clause filters individual rows before GROUP BY, while HAVING filters aggregated groups after GROUP BY.
Q.124
Medium
Database/SQL
Which data structure is most efficient for implementing a LRU (Least Recently Used) cache?
A
Array
B
Hash Map + Doubly Linked List
C
Binary Search Tree
D
Queue only
Correct Answer:
B. Hash Map + Doubly Linked List
Explanation:
Hash Map provides O(1) lookup while Doubly Linked List maintains insertion order and allows O(1) removal/reordering.
Q.125
Medium
Database/SQL
In cloud computing, what does the term 'eventual consistency' refer to?
A
Data is immediately consistent across all nodes
B
Data will become consistent across distributed systems after some time
C
Consistency checks are performed eventually
D
Cloud systems never achieve consistency
Correct Answer:
B. Data will become consistent across distributed systems after some time
Explanation:
Eventual consistency in cloud systems means that data replicas will converge to the same state after all updates have propagated.
Q.126
Medium
Database/SQL
What is the primary benefit of containerization technology like Docker in modern application deployment?
A
Reduces application performance
B
Ensures consistency between development and production environments
C
Eliminates the need for databases
D
Automatically handles all security patches
Correct Answer:
B. Ensures consistency between development and production environments
Explanation:
Docker containers package applications with dependencies, ensuring identical execution across different environments.
Q.127
Medium
Database/SQL
In machine learning, what is a confusion matrix primarily used for?
A
To train neural networks
B
To evaluate classification model performance
C
To normalize feature scaling
D
To generate random datasets
Correct Answer:
B. To evaluate classification model performance
Explanation:
A confusion matrix shows True Positives, True Negatives, False Positives, and False Negatives, enabling comprehensive evaluation of classification accuracy.
Q.128
Medium
Database/SQL
Which encryption standard is currently recommended for securing data in transit over networks?
A
DES
B
MD5
C
TLS 1.3
D
SHA-1
Correct Answer:
C. TLS 1.3
Explanation:
TLS 1.3 is the latest, most secure protocol standard for encrypting data in transit, replacing older protocols like SSL and TLS 1.2.
Q.129
Medium
Database/SQL
What is the time complexity of searching an element in a balanced Binary Search Tree?
A
O(n)
B
O(n log n)
C
O(log n)
D
O(1)
Correct Answer:
C. O(log n)
Explanation:
A balanced BST maintains O(log n) search complexity by keeping the tree height logarithmic relative to node count.
Q.130
Medium
Database/SQL
What is the normal form that ensures no partial dependencies exist in a relation?
A
Third Normal Form (3NF)
B
Boyce-Codd Normal Form (BCNF)
C
Second Normal Form (2NF)
D
First Normal Form (1NF)
Correct Answer:
C. Second Normal Form (2NF)
Explanation:
2NF eliminates partial dependencies where non-key attributes depend on part of a composite key. 3NF further eliminates transitive dependencies.
