26. SQL Databases

pip install sqlalchemy databases asyncpg psycopg2-binary alembic

SQLAlchemy Setup

# database.py
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base

SQLALCHEMY_DATABASE_URL = "sqlite:///./test.db"
# Postgres: "postgresql://user:pass@localhost/db"

engine = create_engine(SQLALCHEMY_DATABASE_URL)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()

Model

# models.py
from sqlalchemy import Column, Integer, String, Float, Boolean
from database import Base

class Item(Base):
    __tablename__ = "items"
    id = Column(Integer, primary_key=True, index=True)
    name = Column(String, index=True)
    price = Column(Float)
    is_offer = Column(Boolean, default=False)

Dependency

# main.py
from fastapi import Depends, FastAPI
from sqlalchemy.orm import Session
from database import SessionLocal, engine
import models

models.Base.metadata.create_all(bind=engine)

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

@app.get("/items/")
def read_items(skip: int = 0, limit: int = 10, db: Session = Depends(get_db)):
    return db.query(models.Item).offset(skip).limit(limit).all()