controllers/test_documents/database.py

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from models import Base

SQLALCHEMY_DATABASE_URL = "sqlite:///database.db"

engine = create_engine(SQLALCHEMY_DATABASE_URL)
Base.metadata.create_all(engine)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

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