is there anyway I can using system.data.oracleclient to perform mass upload from datatable to oracle database?
Per Microsoft: Types in System.Data.OracleClient are deprecated and will be removed in a future version of the .NET Framework.
Microsoft recommends that you use a third-party Oracle provider. A good option is Oracle Data Provider for .NET (ODP.NET).
http://www.oracle.com/technetwork/topics/dotnet/index-085163.html
To answer your specific question, ODP.NET has an array binding feature for bulk inserting.
https://dzone.com/articles/bulk-data-insertion-oracle
http://www.ayobamiadewole.com/Blog/Bulk-Data-Insertion-into-Oracle-Database-in-Csharp
