Reading excel and inserting data in the database

string connectionString = "";
                 if (FileUpload1.HasFile)
                 {
 string fileName = System.IO.Path.GetFileName(FileUpload1.PostedFile.FileName);
 string fileExtension = System.IO.Path.GetExtension(FileUpload1.PostedFile.FileName);
string fileLocation = Server.MapPath("/Upload")+"sample" + fileExtension;                    
                     FileUpload1.SaveAs(fileLocation);                                    

                     if (fileExtension == ".xls")
                     {
                         connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileLocation + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=1\"";                       
                     }
                     else if (fileExtension == ".xlsx")
                     {
                         connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + fileLocation + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=1\"";                       
                     }
                     else if((!fileExtension.Contains(".xls")) ||(!fileExtension.Contains(".xlsx")))
                     {
                           lblStatus.Visible = true;
                         lblStatus.Text = "Uploaded filetype should be .xls or .xlsx";
                         lblStatus.ForeColor = System.Drawing.Color.Red;
                         return;
                     }
                     OleDbConnection con = new OleDbConnection(connectionString);
                     OleDbCommand cmd = new OleDbCommand();
                     cmd.CommandType = System.Data.CommandType.Text;
                     cmd.Connection = con;
                     OleDbDataAdapter dAdapter = new OleDbDataAdapter(cmd);
                     DataTable dtExcelRecords = new DataTable();
                     con.Open();
                     DataTable dtExcelSheetName = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
                     string getExcelSheetName = dtExcelSheetName.Rows[0]["Table_Name"].ToString();
                    
     cmd.CommandText = "SELECT * FROM [" + getExcelSheetName + "]";
                         dAdapter.SelectCommand = cmd;
                         dAdapter.Fill(dtExcelRecords);
                         con.Close();

                   // remove empty rows and columns                 

                     dtExcelRecords = dtExcelRecords.AsEnumerable().Where(row => !row.ItemArray.All(f => f is System.DBNull || String.IsNullOrEmpty(f.ToString()))).CopyToDataTable();
                     for (int col = dtExcelRecords.Columns.Count - 1; col >= 0; col--)
                     {
                         bool removeColumn = true;
                         foreach (DataRow row in dtExcelRecords.Rows)
                         {
                             if (!row.IsNull(col))
                             {
                                 removeColumn = false;
                                 break;
                             }
                         }
                         if (removeColumn)
                             dtExcelRecords.Columns.RemoveAt(col);
                     }