This PDF is a carefully curated Database Interview Questions & Answers preparation guide designed for junior, mid-level, and senior developers.

It focuses on how interviewers expect you to understand SQL, NoSQL, schema design, query optimisation, and production-grade database practices — not just write queries.

What this PDF includes:

• 320+ carefully curated database interview questions

• SQL and NoSQL fundamentals with real behaviour explanations

• PostgreSQL, MongoDB, DynamoDB, and Firebase/Firestore deep dives

• Schema design scenarios for real-world domains (e-commerce, chat, SaaS, etc.)

• SQL query writing scenarios with expected output and optimal solutions

• Indexing, transactions, replication, and sharding strategies

• Production monitoring, performance tuning, and deployment best practices

• Common mistakes and interview traps

Topics covered:

• SQL fundamentals (joins, aggregations, subqueries, window functions)

• NoSQL data modelling (document, key-value, column-family, graph)

• PostgreSQL (CTEs, partitioning, VACUUM, pg_stat_statements)

• MongoDB (aggregation pipeline, sharding, change streams, $lookup)

• DynamoDB (single-table design, GSI/LSI, capacity modes, DAX)

• Firebase/Firestore (security rules, real-time listeners, composite indexes)

• Database design scenarios (30+ whiteboard-style schema challenges)

• SQL query writing scenarios (35 hands-on query challenges with optimal solutions)

• Backup, replication, disaster recovery, and high availability

• Production monitoring, connection pooling, and cost optimisation

Who this is for:

• Backend and full-stack developers at any level

• Engineers preparing for database-focused interviews

• Developers choosing between SQL and NoSQL for new projects

• Engineers wanting deeper understanding of database architecture and performance

This is a PDF-only product, intended for personal use, and works well as a last-mile interview revision guide.