Databases
Database internals, indexing, transactions, and SQL/NoSQL
3 subjects · browse with filters
Database Indexing
Learn how B-tree and hash indexes work internally, how the query planner uses them, when to create composite and covering indexes, and how to diagnose slow queries using EXPLAIN ANALYZE.
Database Replication & Sharding
Learn how single-leader, multi-leader and leaderless replication work, how quorums and failover behave, and how to shard a database by range, hash or directory — with shard-key selection, rebalancing, cross-shard queries and a worked 500M-user example.
SQL vs NoSQL & Data Modeling for Scale
Compare relational databases with key-value, document, wide-column, graph, search and time-series stores, learn access-pattern-driven modelling for DynamoDB and Cassandra, and use a decision matrix to justify database choices in interviews.