

def __init__(self, destination, date_column, window=0, **kwargs):
    'Constructor for the DeltaLoadStep class\n\n        Args:\n            date_column(string): name of column (of type date) to use as the\n                delta value (i.e., only load the last X days)\n            window(int): number of days before last loaded day to update\n            **kwargs(optional): Keyword arguments directly passed to base class\n        '
    dest = Table(SqlScript(filename=parse_path(destination)))
    delta_clause = "\n            WHERE {date_column} >=\n                COALESCE(\n                    (SELECT MAX({date_column}) FROM {destination}),\n                    '1800-01-01'::DATE\n                ) - {window}\n        ".format(date_column=date_column, destination=dest.full_name, window=window)
    super(DeltaLoadStep, self).__init__(destination=destination, filter_clause=delta_clause, **kwargs)

dataset/ETHPy150Open coursera/dataduct/dataduct/steps/delta_load.py DeltaLoadStep.__init__/original