Specifies how data of a streaming DataFrame/Dataset is written to a streaming sink.

        Options include:

        * `append`:Only the new rows in the streaming DataFrame/Dataset will be written to
           the sink
        * `complete`:All the rows in the streaming DataFrame/Dataset will be written to the sink
           every time these is some updates
        * `update`:only the rows that were updated in the streaming DataFrame/Dataset will be
           written to the sink every time there are some updates. If the query doesn't contain
           aggregations, it will be equivalent to `append` mode.

       .. note:: Evolving.

        >>> writer = sdf.writeStream.outputMode('append')

def outputMode(self, outputMode):
        """Specifies how data of a streaming DataFrame/Dataset is written to a streaming sink.

        Options include:

        * `append`:Only the new rows in the streaming DataFrame/Dataset will be written to
           the sink
        * `complete`:All the rows in the streaming DataFrame/Dataset will be written to the sink
           every time these is some updates
        * `update`:only the rows that were updated in the streaming DataFrame/Dataset will be
           written to the sink every time there are some updates. If the query doesn't contain
           aggregations, it will be equivalent to `append` mode.

       .. note:: Evolving.

        >>> writer = sdf.writeStream.outputMode('append')
        """
        if not outputMode or type(outputMode) != str or len(outputMode.strip()) == 0:
            raise ValueError('The output mode must be a non-empty string. Got: %s' % outputMode)
        self._jwrite = self._jwrite.outputMode(outputMode)
        return self