背景：一个存储操作，存储时涉及多张表的数据录入，期望是如果某张表录入出错，多张表同时回滚，这里使用嵌套事务

# 添加事务处理方法

	from contextlib import ContextDecorator


	def atomic(db):
	if callable(db):
	return Atomic(db)(db)
	else:
	return Atomic(db)


	class Atomic(ContextDecorator):

	def __init__(self, db):
	self.db = db

	def __enter__(self):
	pass

	def __exit__(self, exc_typ, exc_val, tb):
	if exc_typ:
	self.db.session.rollback()
	else:
	self.db.session.commit()

# 在需要做嵌套事务的方法中调用上述方法

	from dashboard.model.common import atomic
	# db = SQLAlchemy()
	# logging.basicConfig(level=logging.INFO, format="%(asctime)s %(process)d:%(thread)d %(filename)s:%(lineno)d:%(levelname)s:%(message)s")
	# logger = logging.getLogger(__name__)
	from dashboard import logger, db


	def add_data():
	logger.info("user save data")
	with atomic(db):
	xxxbiz.add_data1(data)
	xxxbiz.add_data2(data)
	xxxbiz.add_data3(data)
	xxxbiz.add_data4(data)
	xxxbiz.add_data5(data)
	logger.info("save data success")