Databases for backend/AI-engineer interviews — Google, Microsoft, Amazon. Every page explains why a database behaves the way it does, then the trade-off your design takes on.
Tier 1 — master these first: SQL, JOINs, Indexes, Transactions & ACID, Isolation Levels, Locks & Concurrency, Deadlocks, Query Optimization, Normalization, Replication, Sharding, CAP, SQL vs NoSQL, Redis & Caching, Schema Design.
Tier 2 — strong understanding: Window Functions & CTEs, Storage Internals & WAL, MVCC, Connection Pooling, Database Security, Distributed Databases & Quorums.
For your Backend + AI target, right after Tier 1: pgvector & vector databases, embeddings storage, similarity search, hybrid search.
Tier 3 — learn after these: Two-Phase Commit, Saga, CDC, Event Sourcing, CQRS, Materialized Views, Database Recovery, Raft/Paxos, distributed-database internals.