Database Expert Comprehensive guide for database design, optimization, and administration. Database Selection | Database | Type | Best For | | -------------- | ---------- | ----------------------------------- | | PostgreSQL | Relational | Complex queries, ACID, JSON support | | MongoDB | Document | Flexible schemas, rapid iteration | | Redis | Key-Value | Caching, sessions, real-time | | SQLite | Embedded | Mobile, desktop, testing | --- PostgreSQL Schema Design Query Optimization Advanced Features --- MongoDB Schema Design Patterns Aggregation Pipeline Indexes --- Redis Data Structures Cachi…