Phase 3 — Relational Databases, SQL, FastAPI & Django

The heart of almost every mid-to-senior backend role is data modeling, SQL query optimization, and API engineering. In Phase 3, you master PostgreSQL internals (SQL Performance Explained & DDIA), SQLAlchemy 2.0, FastAPI, Django/DRF, and production authentication/security.

Modules & Lessons

01 — PostgreSQL & SQL Mastery

• 01-relational-design-and-normalization — 3NF vs denormalization, data types (UUID, JSONB, TIMESTAMPTZ), constraints, and foreign keys
• 02-advanced-sql-and-window-functions — CTEs, window functions (ROW_NUMBER, LAG), aggregations, and UPSERT (ON CONFLICT)
• 03-indexing-and-explain-analyze — Heap files, B-Tree, GIN, partial/composite indexes, reading EXPLAIN (ANALYZE, BUFFERS), and seq-scan traps
• 04-transactions-acid-and-isolation — ACID, MVCC, Read Committed vs Repeatable Read vs Serializable, lost updates, and SELECT ... FOR UPDATE

02 — SQLAlchemy 2.0 & Data Access Architecture

• 01-sqlalchemy-core-and-orm — Engine, connection pooling, Session lifecycle, Unit of Work, and modern 2.0 select() syntax
• 02-n-plus-one-and-pagination — Eager loading (selectinload, joinedload), offset vs keyset (cursor) pagination, and Alembic migrations

03 — FastAPI Production Engineering

• 01-routing-validation-and-di — Pydantic v2 schemas, custom validators, Dependency Injection lifecycle, and OpenAPI contracts
• 02-middleware-errors-and-testing — RFC 7807 Problem Details error envelopes, correlation ID middleware, and integration tests with real DB transactions

04 — Django for Backend Engineers

• 01-django-architecture-and-orm — Django request lifecycle, Models, QuerySet lazy evaluation, select_related/prefetch_related, and migrations
• 02-drf-signals-and-admin — Django REST Framework views/serializers, customizing Django Admin for ops, and when to choose Django vs FastAPI

05 — Authentication, Authorization & Security

• 01-passwords-sessions-and-jwt — Argon2id hashing, stateful sessions vs stateless JWT, refresh token rotation, and revocation
• 02-oauth2-rbac-and-owasp — OAuth2 flows, Role-Based Access Control (RBAC), SQLi, SSRF, CSRF, CORS, and secret management

Capstone Milestone: pulseforge/ v0.4

Back PulseForge with PostgreSQL and SQLAlchemy 2.0, build the high-throughput FastAPI ingestion & keyset-paginated query service, add a Django Admin & DRF tenant management portal, and secure everything with Argon2 + JWT + RBAC.