Database Integration (SQLite + SQLAlchemy)

# 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()