backref 用法

源码

def backref(name, **kwargs):
    """Create a back reference with explicit keyword arguments, which are the same arguments one can send to :func:`relationship`.

    Used with the ``backref`` keyword argument to :func:`relationship` in place of a string argument, e.g.::

        'items':relationship(
            SomeItem, backref=backref('parent', lazy='subquery'))

    .. seealso::

        :ref:`relationships_backref`

    """

    return (name, kwargs)