Learn it, then nail the interview
Transactions, ACID, isolation levels, locking & MVCC, distributed transactions, SQL and NoSQL — full story-driven chapters to learn it from scratch, plus a real interview question bank to prove you know it.
What's inside
Learn From Scratch
Story-driven chapters that build every concept from first principles — the bank-counter story, isolation levels, locking, MVCC, distributed transactions — with code examples throughout.
Real Interview Questions
A curated question bank drawn straight from the material, with an AI tutor that builds a complete zero-to-expert answer for every question, on demand.
Diagrams, Chat & Flashcards
Generate a visual diagram for any topic or question, ask the AI tutor a follow-up, and review with spaced-repetition flashcards that bring weak spots back sooner.
Categories
Transaction Mastery
ACID, isolation levels, locking & MVCC, Spring @Transactional internals, distributed transactions (2PC, Saga, Outbox/CDC), and Kafka transactions — from the bank-counter story to production incident response.
SQL
DDL/DML, JOINs, subqueries, indexes, transactions, isolation levels, locking, window functions, CTEs, query performance, and database design — PostgreSQL, MySQL, SQL Server & Oracle.
NoSQL
MongoDB, Redis, Cassandra, Neo4j, CAP theorem, BASE, distributed systems, caching patterns & CQRS.