I am trying to access two different data sources i.e one oracle and other CSV file in same report.
Please suggest me how can I achieve this
You could define a so call "SubDataSource" within your design, where one is for accessing your oracle database via an select (Connection must be passed from Outside, when filling the report) and the second one could access your csv file (filename could be passed as parameter or hardcoded or whatever).
The SubDataSources could be used for SubReports or ListElements or Crosstabs or Tables.....
You could also just use the main datasource (e.g. the sql oracle one) for filling process of the MasterReport and just the CSV-SubDataSource for a integrated SubReport.
So just give it a try.
hth + regards