This chapter builds up, step by step for junior engineers, the idea of normalization for eliminating data duplication and contradictions (update, insertion, and deletion anomalies) — from functional dependency, through first to third normal form, a note on BCNF, and selective denormalization for performance.
This chapter shows junior engineers, through two examples — a restaurant order slip and an internal SNS — the end-to-end process of extracting entities from a form or business requirements, building an ER diagram, normalizing it, and reaching CREATE TABLE.
Through two comprehensive case studies — a "product delivery management system" and a "task management system" — this chapter practices the full flow of requirements → ER diagram → table definitions → expected queries, integrating the concepts learned across earlier chapters as the capstone of this guide.
This chapter explains why database design plays a role like a building's foundation, the qualitative reasons it's hard to fix later (you can't stop a live service, data-migration costs, the breadth of impact), and why data-design skills remain valuable even in the AI era.
This chapter explains, for junior engineers, where database design fits within the overall flow of system development, and how the conceptual, logical, and physical design stages move from abstract to concrete.
A practical guide for junior engineers just starting to design DB schemas for an API backend or a business application. Across 19 chapters plus a glossary and a design template collection — Part 1 Fundamentals → Part 2 Design → Part 3 Applied → Part 4 Practice — you'll learn to go from requirements through ER diagrams and table definitions to SQL, by reading straight through.