我现在在写数据库代码 ，下面是一段现在我还有一个Save（），请问我该怎么写啊？
 public Parcel GetParcel(string SQL)
        {
            Parcel myParcel = new Parcel();
            CreateConnection().Open();
            SqlDataReader Dr;
            try
            {
                SqlCommand Cmd = new SqlCommand(SQL, CreateConnection());
                Dr = Cmd.ExecuteReader();
               
            }
            catch
            {
                throw new Exception(SQL);
            }
            if (Dr.Read())
            {
                myParcel.ID = Convert.ToString(Dr[0]);
                myParcel.Gamma.AlarmValue = Convert.ToInt32(Dr[1]);
                myParcel.Gamma.MaxValue = Convert.ToInt32(Dr[2]);
                myParcel.ENose.AlarmValue = Convert.ToInt32(Dr[3]);
                myParcel.ENose.MaxValue = Convert.ToInt32(Dr[4]);
                myParcel.ExImage.FileName = Convert.ToString(Dr[5]);
                myParcel.XRay.Alarmed = Convert.ToBoolean(Dr[6]);
                myParcel.XRay.FileName = Convert.ToString(Dr[7]);
                myParcel.XRay.ToPush = Convert.ToInt16(Dr[8]);
            }
            Dr.Close();
            CreateConnection().Close();
            return myParcel;
        }
        public void Save(Parcel myParcel)
        {
            
        }

判断数据库中有相应数据,有的话就用update更新原有数据,没的话就用insert into 语句把数据插入数据库
用 cmd.ExecuteNonQuery();