NoSQL & Data Models

Relational, document, key-value, wide-column, graph, search, time-series and vector are not a ladder from old to scalable; each is a different bet on which access pattern you will need most, and the price is the patterns you give up.

A document store trades joins for locality — the whole object arrives in one read — and the design decision that replaces normalization is whether each relationship is embedded in the parent or referenced by id.

Four specialised models, each built around one query shape: partition-local time-ordered reads at huge write rates, multi-hop traversal, relevance-ranked text, and range aggregates over time.