# database.py from sqlalchemy import create_engine, Column, Integer, String from sqlalchemy.orm import declarative_base, sessionmaker Base = declarative_base() class User(Base): __tablename__ = "users" id = Column(Integer, primary_key=True) username = Column(String(50), unique=True) hashed_password = Column(String(100)) # Initialize once in app.py engine = create_engine("sqlite:///database.db") Base.metadata.create_all(engine) SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine) # Dependency def get_db(): db = SessionLocal() try: yield db finally: db.close()