7
Phase 7 · 1–2 months
Databases
Every real app needs to remember things even after it is closed. That is what a database is for.
What to learn
- SQL (= the language for asking a database questions): SELECT, WHERE, INSERT, UPDATE, DELETE, and JOIN (= joining two tables together).
- PostgreSQL (= a popular, powerful, free database).
- Good table design and normalization (= not storing the same thing twice).
- ORM (= a tool that lets you use the database with normal code instead of database commands).
- Easy modern option: Supabase (= a ready-made online database with login built in).
Videos to watch
Practice on your own
- On paper, design 3 tables (users, posts, comments) and draw how they connect.
- Write a question that finds and sorts some rows.
- Write a JOIN across two tables.
- Connect your Phase 6 API to a real database.
Build this
Add a real database to your backend so the data stays after restart — and link it (one user has many tasks).
Move on when: Your To-Do app keeps its data forever, in a real database, linked to each user.