sqlalchemy检查会话包含的更改数量

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

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

# 创建基类模型
Base = declarative_base()

# 定义数据模型
class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    name = Column(String)

# 创建会话对象
session = Session()

# 添加新对象
user1 = User(name='Alice')
user2 = User(name='Bob')
session.add_all([user1, user2])

# 修改对象
user1.name = 'New Alice'

# 删除对象
session.delete(user2)

# 检查更改数量
new_count = len(session.new)
dirty_count = len(session.dirty)
deleted_count = len(session.deleted)

print(f"New objects count: {new_count}")
print(f"Modified objects count: {dirty_count}")
print(f"Deleted objects count: {deleted_count}")