确保值与 mongoengine 中的其他值存在

Question

我知道 mongoengine 你可以设置 unique_with 之类的东西，但我想设置一个约束 "if param_1 is True, param_2 must not be null." 有没有办法在 mongoengine 中做到这一点？处理此问题的最佳方法是在 update/save 方法中设置条件吗？

class Doc(Document):
    param_1 = BooleanField()
    param_2 = StringField()

    def save(self, *args, **kwargs):
        # DO SOMETHING HERE TO MAKE SURE
        # IF param_1 == True, param_2 != None
        super(Doc, self).save(*args, **kwargs)

Answer 1

最简单的方法是使用 signals。

class Doc(Document):
    param_1 = BooleanField()
    param_2 = StringField()

    @classmethod
    def pre_save(cls, sender, document, **kwargs):
        if (document.param_1 is True) and (document.param_2 is None):
            raise ValueError("If param_1 is True then param_2 cannot be None")

signals.pre_save.connect(Document.pre_save, sender=Document)

确保值与 mongoengine 中的其他值存在

making sure value exists with other value in mongoengine

python

mongoengine