input: [Option name] date_format [Option type] integer [Example] INGRES_DATE_MULTINATIONAL4 [Description] 
output: Sets the allowable input and output format for Ingres dates. Defaults to the value defined by II_DATE_FORMAT. If II_DATE_FORMAT is not set the default date format is US, e.g. mm/dd/yy. Valid values for date_format are: INGRES_DATE_DMY INGRES_DATE_FINISH INGRES_DATE_GERMAN INGRES_DATE_ISO INGRES_DATE_ISO4 INGRES_DATE_MDY INGRES_DATE_MULTINATIONAL INGRES_DATE_MULTINATIONAL4 INGRES_DATE_YMD INGRES_DATE_US