SQL & Data Modeling
maang.io System Design Series
Good data modeling is the foundation of every relational system. This deep dive covers the relational model — keys, normalization (1NF→BCNF) to remove anomalies, indexes (B+trees) that change query plans, and joins — plus when to deliberately denormalize for performance. Get the model right and everything downstream is easier.
This deep dive comes in three parts:
- Foundations & Core Concepts — relations, keys, and normalization.
- Internals — B+tree indexes, join strategies, and denormalization trade-offs, with worked numbers.
- Interview — Staff/Principal Q&A: schema design, indexing, and normalize-vs-denormalize.