2026

Databases Interview Questions 2026

A current, 2026 snapshot of the Databases interview questions worth knowing — kept up to date as frameworks and best practices evolve, so you prepare with what companies are actually asking in 2026.

60Questions14Beginner13Intermediate33Senior

60 Databases questions

  1. 1Difference between Optimistic and Pessimistic Locking.Intermediate
  2. 2What is the CAP Theorem?Intermediate
  3. 3What is a View and why use it?Intermediate
  4. 4Explain the concept of 'Deadlock' in DB transactions.Intermediate
  5. 5What is Database Sharding?Intermediate
  6. 6What are Database Triggers and Stored Procedures?Intermediate
  7. 7Explain the difference between Clustered and Non-Clustered Indexes.Intermediate
  8. 8What is an Execution Plan?Intermediate
  9. 9SQL vs NoSQL: When to choose which?Intermediate
  10. 10Explain Database Transactions and Isolation Levels.Intermediate
  11. 11What is a NULL value in SQL?Beginner
  12. 12What is a Database Schema?Beginner
  13. 13Explain the difference between WHERE and HAVING clauses.Beginner
  14. 14What is an Index in a database?Beginner
  15. 15What are Joins in SQL?Beginner
  16. 16Difference between DELETE, TRUNCATE, and DROP.Beginner
  17. 17What is Database Normalization?Beginner
  18. 18What is a Primary Key and a Foreign Key?Beginner
  19. 19Explain the ACID properties in Databases.Beginner
  20. 20What is the difference between DBMS and RDBMS?Beginner
  21. 21Databases Interview Question 1 (Free)Beginner
  22. 22Databases Interview Question 5 (Free)Intermediate
  23. 23Databases Interview Question 4 (Free)Beginner
  24. 24Databases Interview Question 3 (Free)Senior
  25. 25Databases Interview Question 2 (Free)Intermediate
  26. 26The future of Serverless Databases and Auto-scaling.Senior
  27. 27Database performance tuning using Wait Events and Profiling.Senior
  28. 28Polyglot Persistence: Combining multiple DB types in one microservice.Senior
  29. 29Understanding Read-after-Write consistency in distributed nodes.Senior
  30. 30Bloom Filters in Database search optimization.Senior
  31. 31Compaction strategies in NoSQL Databases.Senior
  32. 32The role of Proxy layers (PgBouncer/MaxScale) in DB scaling.Senior
  33. 33Designing a Multi-tenant Database: Row-level vs Schema-level.Senior
  34. 34Distributed Tracing and Observability for Database Queries.Senior
  35. 35Database Indexing for JSON and semi-structured data.Senior
  36. 36Security: SQL Injection prevention at the driver and engine level.Senior
  37. 37Partitioning strategies: Range, List, Hash, and Composite.Senior
  38. 38Time-series Database architecture (InfluxDB/Timescale).Senior
  39. 39Vector Databases for AI and LLM Embeddings.Senior
  40. 40Database connection pooling: Bottlenecks and Tuning.Senior
  41. 41Optimizing Databases for SSDs vs HDDs.Senior
  42. 42Write-Ahead Logging (WAL) and Crash Recovery logic.Senior
  43. 43Columnar Storage (Parquet/Cassandra) for Analytics.Senior
  44. 44Graph Databases (Neo4j) vs Relational for relationship-heavy data.Senior
  45. 45Materialized Views: Refresh strategies and performance.Senior
  46. 46Implementing Change Data Capture (CDC).Senior
  47. 47Data Warehousing vs Data Lakes vs Lakehouses.Senior
  48. 48Handling Hotspots in Sharded Databases.Senior
  49. 49Deep dive into MVCC (Multi-Version Concurrency Control).Senior
  50. 50Managing Schema Migrations in high-traffic environments.Senior
  51. 51Master-Slave vs Multi-Master Replication challenges.Senior
  52. 52Distributed Databases and Consensus Protocols (Paxos/Raft).Senior
  53. 53Database Query Optimization: Statistics and Histograms.Senior
  54. 54B-Trees vs LSM Trees: Internal storage mechanics.Senior
  55. 55Architecting for High Availability: Replication vs Clustering.Senior
  56. 56Databases Advanced Interview Question 9Senior
  57. 57Databases Advanced Interview Question 8Intermediate
  58. 58Databases Advanced Interview Question 7Beginner
  59. 59Databases Advanced Interview Question 6Senior
  60. 60Databases Advanced Interview Question 10Beginner

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Frequently asked questions

Are these Databases interview questions up to date for 2026?

Yes. This page reflects 60 Databases interview questions kept current with today's frameworks, tooling and interview trends, with each answer maintained and dated.

What Databases topics should I focus on in 2026?

Prioritise the fundamentals plus the modern patterns interviewers ask about now. Each question here includes a detailed answer, code example and common mistakes so you can target the highest-impact areas.

Are these questions free?

You can read the question and a short answer for free. A subscription unlocks the full detailed explanation, real-world example, common mistakes and follow-up questions for each one.