在SQLAlchemy中更新现有的子对象并将新的子对象附加到父对象的有效方法是什么？

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

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

# 创建基类
Base = declarative_base()

# 定义父表对象
class Parent(Base):
    __tablename__ = 'parents'
    id = Column(Integer, primary_key=True)
    name = Column(String)
    children = relationship("Child")

# 定义子表对象
class Child(Base):
    __tablename__ = 'children'
    id = Column(Integer, primary_key=True)
    name = Column(String)
    parent_id = Column(Integer, ForeignKey('parents.id'))

# 查询需要更新的父对象
parent = session.query(Parent).filter_by(name='父对象名称').first()

# 创建新的子对象
new_child = Child(name='新子对象名称')

# 合并子对象到父对象
merged_parent = session.merge(parent)
merged_parent.children.append(new_child)

# 保存更新
session.commit()