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.
A collection of exercises to deepen the understanding of normalization covered in Chapter 11. Practice decomposing an unnormalized table up through third normal form, repeatedly, using common business cases (children's information, multiple categories, derived values, employee information).
Integrates the DDD and clean architecture learned so far, implementing the 4 layers (presentation / application / domain / infrastructure) using the order creation and confirmation APIs as the subject. Summarizes each layer's responsibilities, the flow of data transformation, and layered tests (domain / UseCase / Repository) to bring the whole picture together.