当使用sqlalchemy declarative设置不存在的属性时,如何引发错误

好的,解决方案似乎是覆盖 __setattr__ 方法,它允许我们在设置前检查atribute是否已经存在。

class BaseBase(object):
    """
    This class is a superclass of SA-generated Base class,
    which in turn is the superclass of all db-aware classes
    so we can define common functions here
    """

    def __setattr__(self, name, value):
        """
        Raise an exception if attempting to assign to an atribute which does not exist in the model.
        We're not checking if the attribute is an SQLAlchemy-mapped column because we also want it to work with properties etc.
        See http://stackoverflow.com/questions/12032260/ for more details.
        """ 
        if name != "_sa_instance_state" and not hasattr(self, name):
            raise AttributeError("Attribute %s is not a mapped column of object %s" % (name, self))
        super(BaseBase, self).__setattr__(name, value)

Base = declarative_base(cls=BaseBase)

有点像炼金术的“严格模式”。。。

覆盖 __get__ 方法,并检查它是否在列中(通过将其与类定义或运行时搜索一起存储)

更多信息 here 从那时起。