提示 数据导入成功  但是查库里无数据   求解 

备注：dt 为将要导入的数据  ，tablename 将要导入的表名
void CZDataSource(DataTable dt,string tablename)
        {
            var sql = string.Format("select * from {0} ", tablename);
  
            using(OracleConnection con=new OracleConnection(DBHelp.dbConnectionString))
            {
                con.Open();
                OracleTransaction tran = con.BeginTransaction();
                OracleCommand cmd = new OracleCommand(sql, con);
                OracleDataAdapter adapter = new OracleDataAdapter(cmd);
           
                cmd.Transaction = tran;
                try
                {
                    DataTable dss = new DataTable();
                    adapter.Fill(dss);
                  
                    dss.Merge(dt);    // 数据合并             
                   adapter.UpdateBatchSize = 600;
                    OracleCommandBuilder cb = new OracleCommandBuilder(adapter);
                 
                    DataTable dssfb = dss.GetChanges();
                    if (dssfb != null)
                    {
                        adapter.Update(dssfb);  // 这里更新表的副本但是提示为null 
                    }
                    else
                    {
                        adapter.Update(dss);
                    }
                    dss.AcceptChanges();
                    tran.Commit();
                   My.ClientScript.Alert(this, "同步数据成功！");
                }
                catch(Exception ex)
                {
                    tran.Rollback();
                    My.ClientScript.Alert(this, "同步数据失败！"+ex.Message.ToString());
                    con.Close();
                }
            }
 
        }