schema.py 文件源码

def is_to_one_relationship(field):
    """
    Returns True, if the *field* is a reference field:

    *   :class:`mongoengine.ReferenceField`
    *   :class:`mongoengine.CachedReferenceField`
    *   :class:`mongoengine.GenericReferenceField`

    All of these fields describe a *to-one* relationship.
    """
    return isinstance(field, mongoengine.ReferenceField)\
        or isinstance(field, mongoengine.CachedReferenceField)\
        or isinstance(field, mongoengine.GenericReferenceField)