base.py 文件源码

def define_constraint_cascades(self, constraint):
        text = ""
        if constraint.ondelete is not None:
            text += " ON DELETE %s" % constraint.ondelete

        # oracle has no ON UPDATE CASCADE -
        # its only available via triggers
        # http://asktom.oracle.com/tkyte/update_cascade/index.html
        if constraint.onupdate is not None:
            util.warn(
                "Oracle does not contain native UPDATE CASCADE "
                "functionality - onupdates will not be rendered for foreign "
                "keys.  Consider using deferrable=True, initially='deferred' "
                "or triggers.")

        return text