title: OracleBulkCopy from CSV - Can not insert null column has value
body: <p>I am using OracleBlukCopy to dump a huge CSV file into the database table. Here is the code I am using. When I run this I am getting an error saying cannot insert NULL into TBL_COL1, but my CSV has values for TBL_COL1.</p>
  
  <p>After research I came to conclusion that it is giving an error when TBL_COL1 has characters in it. Any idea why?</p>
  
  <pre><code>DataTable datatable = TranslateCSVFileToDataTable();
  
  using (OracleConnection connectiontodb = new OracleConnection(databaseconnectionstring))
  {
      connectiontodb.Open();
      using (OracleBulkCopy copytothetable = new OracleBulkCopy(connectiontodb))
      {
          copytothetable.ColumnMappings.Add("TBL_COL1", "TBL_COL1"); 
          copytothetable.ColumnMappings.Add("TBL_COL2", "TBL_COL2"); 
          copytothetable.ColumnMappings.Add("TBL_COL3", "TBL_COL3"); 
          copytothetable.DestinationTableName = "DESTINATION_TABLE";
          copytothetable.WriteToServer(datatable);
      }
  }
  
  
  CREATE TABLE DESTINATION_TABLE
  (
    TBL_COL1                   VARCHAR2(32) not null,
    TBL_COL2                   DATE not null,
    TBL_COL3                   DATE not null,
  )
  
  
  98987987987987987,6/23/2014,7/23/2014
  98987987987987987,7/23/2014,8/21/2014
  98987987987987987,8/21/2014,9/22/2014
  98987987987987987,9/22/2014,10/21/2014
  98987987987987987,10/21/2014,11/20/2014
  98987987987987987,11/20/2014,12/22/2014
  656666666666666ABC1234,1/8/2014,1/9/2014
  656666666666666ABC1234,1/9/2014,2/9/2014
  656666666666666ABC1234,2/9/2014,3/9/2014
  656666666666666ABC1234,3/9/2014,4/7/2014
  656666666666666ABC1234,4/7/2014,5/7/2014
  656666666666666ABC1234,5/7/2014,6/8/2014
  656666666666666ABC1234,6/8/2014,7/8/2014
  656666666666666ABC1234,7/8/2014,8/7/2014
  656666666666666ABC1234,8/7/2014,9/8/2014
  656666666666666ABC1234,9/8/2014,10/7/2014
  656666666666666ABC1234,10/7/2014,11/9/2014
  656666666666666ABC1234,11/9/2014,12/7/2014
  777777777777777XYZ1234,5/7/2014,6/8/2014
  777777777777777XYZ1234,6/8/2014,7/8/2014
  777777777777777XYZ1234,7/8/2014,8/7/2014
  777777777777777XYZ1234,8/7/2014,9/8/2014
  777777777777777XYZ1234,9/8/2014,10/7/2014
  777777777777777XYZ1234,10/7/2014,11/9/2014
  777777777777777XYZ1234,11/9/2014,12/7/2014
  </code></pre>