Python reference

SQLAlchemy
cheat sheet.

SQLAlchemy ORM and Core queries, relationships, transactions, async sessions, and FastAPI integration, with Python and SQL examples.

27 topics114 code examplesUpdated 22 Oct 2026

How SQLAlchemy fits together

01Model describesClasses and tables define data.

02Statement buildsPython expressions become SQL.

03Session runsOne transaction tracks changes.

04Database commitsRows are stored or rolled back.

Jump to a specific topic

Choose a chapter

4 chapters · 27 topics

CHAPTER 01 / 04

Define SQLAlchemy models and manage sessions, CRUD, and SELECT queries. Compare Python with SQL and load relationships without N+1 queries.

9 topics

CHAPTER 02 / 04

Write SQLAlchemy bulk updates, subqueries, CTEs, and window functions. Use AsyncSession safely and connect database sessions to FastAPI.

8 topics

CHAPTER 03 / 04

Extend SQLAlchemy mappings and inheritance, run Core transactions, and configure dialects, isolation, and events with Python and SQL examples.

6 topics

CHAPTER 04 / 04

Diagnose SQLAlchemy query performance, handle transaction conflicts, and test database behavior. Includes Alembic migrations and SQL checks.

4 topics