在POST时Sqlalchemy检查记录是否已存在并发回现有记录

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String

Base = declarative_base()

class User(Base):
    __tablename__ = 'users'

    id = Column(Integer, primary_key=True)
    name = Column(String)
    email = Column(String, unique=True)

# 创建数据库引擎和Session
engine = create_engine('数据库连接字符串')
Session = sessionmaker(bind=engine)
session = Session()

# 检查记录是否已存在并返回现有记录
def check_and_get_existing_record(email):
    existing_user = session.query(User).filter(User.email == email).first()
    return existing_user