Networks and Databases

Engineering

Understand how the internet routes data across the globe, how databases store and retrieve it efficiently, and how APIs connect systems together.

55 XP
Reward
11
Questions
5–10 min
Time
Q1 Question 1 of 11

When you visit 'www.example.com' in a browser, your computer cannot route data to it until it has an IP address. Which service performs this translation and how is it structured?

Q2 Question 2 of 11

TCP provides 'reliable, ordered delivery' of packets. What does this mean, and what cost does TCP pay for these guarantees compared to UDP?

Q3 Question 3 of 11

HTTPS adds TLS encryption on top of HTTP. What specific threats does HTTPS protect against that plain HTTP does not?

Q4 Question 4 of 11

A database table 'Orders' has a column 'customer_id' that refers to the primary key of a 'Customers' table. What is 'customer_id' called, and what integrity rule does it enforce?

Q5 Question 5 of 11

A query against a 50-million-row sales table takes 45 seconds without an index but 0.02 seconds after adding an index on the 'product_id' column. What does an index do to achieve this?

Q6 Question 6 of 11

A retail website uses a relational (SQL) database for order history and a Redis key-value (NoSQL) store for session management. Why is this split architecture sensible?

Q7 Question 7 of 11

What does the 'A' in ACID database properties stand for, and why is it essential for a banking transfer that debits one account and credits another?

Q8 Question 8 of 11

A REST API uses HTTP verbs. A mobile app wants to retrieve a list of products. Which HTTP verb and URL convention is correct according to REST principles?

Q9 Question 9 of 11

A SQL JOIN combines rows from two tables. If an 'Orders' table and a 'Customers' table share a 'customer_id' column, what does a JOIN allow you to do?

Q10 Question 10 of 11

Packet switching routes individual data packets independently across the internet. Why is this more resilient than circuit switching (which reserves a fixed path for the entire communication)?

Q11 Question 11 of 11

A developer stores API keys in JSON responses sent to mobile app users so the app can authenticate API calls. What is the critical security flaw in this approach?