I found two approaches to working with databases in FastAPI. Are there any fundamental differences? if so which approach is preferable?
Approach 1This is found in official FastAPI-fullstack example :
from fastapi import Dependsfrom sqlalchemy.orm import sessionmakerfrom sqlalchemy import create_engineengine = create_engine(SQLALCHEMY_DATABASE_URI, pool_pre_ping=True)SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)def get_db() -> Generator: try: db = SessionLocal() yield db finally: db.close()def get_current_user( db: Session = Depends(get_db), token: str = Depends(reusable_oauth2)) -> models.User: ...Approach 2Following approach found in official FastAPI docs, some blogs and also in fastapi_users package documentation:
import databasesDATABASE_URL = "sqlite:///./test.db"database = databases.Database(DATABASE_URL)@app.on_event("startup")async def startup(): await database.connect()@app.on_event("shutdown")async def shutdown(): await database.disconnect()Edit (2021-09-06) - Approach 3
Another way recommended in the new SQLModel package docs by tiangolo himself. This seems like just a variant of the first approach above, but for sake of completeness:
https://sqlmodel.tiangolo.com/tutorial/fastapi/session-with-dependency/
sqlite_file_name = "database.db"sqlite_url = f"sqlite:///{sqlite_file_name}"connect_args = {"check_same_thread": False}engine = create_engine(sqlite_url, echo=True, connect_args=connect_args)def get_session(): with Session(engine) as session: yield session# Code here omitted 👈@app.post("/heroes/", response_model=HeroRead)def create_hero(*, session: Session = Depends(get_session), hero: HeroCreate): db_hero = Hero.from_orm(hero) session.add(db_hero) session.commit() session.refresh(db_hero) return db_hero
