Key-value stores are the simplest NoSQL model:
Structure: Just keys and values. No schema, no relationships. Think of a hash table that persists to disk.
Examples:
- Redis: In-memory, sub-millisecond latency, supports complex data types
- DynamoDB: Managed, auto-scaling, single-digit millisecond response
- Memcached: Pure caching, simpler than Redis
Operations: Get, set, delete. Basic operations run in time. Perfect for caching, session storage, and simple lookups.
Limitations: No queries by value. You must know the exact key.