RDBMS · NoSQL · Beyond

Database Systems

Explore relational and non-relational databases side by side — when to use SQL vs document stores, how indexing works, and what interviewers expect at FAANG and startups.

Quick Compare

Pick the right database type

TypeBest forExamplesTrade-off
RelationalTransactions, reporting, joinsPostgreSQL, MySQLSchema rigidity
DocumentFlexible JSON documentsMongoDB, FirestoreJoin complexity
Key-valueCache, sessions, rate limitsRedis, DynamoDBLimited query patterns
GraphRelationships, recommendationsNeo4j, NeptuneNiche, ops overhead