c# - 从 CSV 执行 SQL INSERT 时如何避免重复数据

Question

从 CSV 文件插入 SQL Server 2008 时如何避免重复数据？

 #region Put to SQL
                string line = null;
                bool IsFirst = true;

                string SqlSyntax = "INSERT INTO ORDRE ";
                string sqlkey = "";
                string sqlvalSELECT = "";

                using (StreamReader sr = File.OpenText(filePath + "\\" + downloadname))
                {
                    while ((line = sr.ReadLine()) != null)
                    {
                        string[] data = line.Split(';');

                        if (!String.IsNullOrEmpty(sqlvalSELECT)) sqlvalSELECT += "\nUNION ALL ";

                        if (data.Length > 0)
                        {
                            string sqlval = "";
                            foreach (object item in data)
                            {
                                if (IsFirst)
                                {
                                    if (!String.IsNullOrWhiteSpace(sqlkey)) sqlkey += ",";
                                    sqlkey += item.ToString();

                                }
                                else
                                {
                                    if (!String.IsNullOrEmpty(sqlval)) sqlval += ",";
                                    sqlval +=  item.ToString();
                                }
                            }
                            if (!String.IsNullOrEmpty(sqlval)) sqlvalSELECT += "SELECT " + sqlval;

                            IsFirst = false;

                        }
                    }
                }


                string sqlTOTAL = SqlSyntax + "(" + sqlkey + ")" + sqlvalSELECT;
                //lbl_Message.Text = sqlTOTAL;

                try
                {
                    using (var connectionWrapper = new Connexion())
                    {
                        var connectedConnection = connectionWrapper.GetConnected();
                        SqlCommand comm_Ftp_Insert = new SqlCommand(sqlTOTAL, connectionWrapper.conn);
                        comm_Ftp_Insert.ExecuteNonQuery();

                    }
                }
                catch (Exception ex)
                {
                    throw new Exception(ex.Message);
                }

                #endregion

我制定了收集已导入 SQL Server 2008 的数据的方法。 我如何将其与 CSV 文件进行比较？

 /// <summary>
        /// Get the existed data on SQL
        /// </summary>
        /// <returns>Return List of Pers_Ordre with key OrdreId and ClientID</returns>
        public List<Pers_Ordre> Get_Existed()
        {
            try
            {
                using (var connectionWrapper = new Connexion())
                {
                    var connectedConnection = connectionWrapper.GetConnected();
                    List<Pers_Ordre> oListOdr = new List<Pers_Ordre>();

                    string sql_Syntax = Outils.LoadFileToString(HttpContext.Current.Server.MapPath("~/SQL/OrdreFTP_GetExist.sql"));
                    SqlCommand comm_Command = new SqlCommand(sql_Syntax, connectionWrapper.conn);

                    SqlDataReader readerOne = comm_Command.ExecuteReader();
                    while (readerOne.Read())
                    {
                        Pers_Ordre oPersOrdre = new Pers_Ordre();
                        oPersOrdre.OrdreId = Convert.ToInt32(readerOne["NO_ORDRE"]);
                        oPersOrdre.ClientID = readerOne["CODE_CLIENT"].ToString();                   
                        oListOdr.Add(oPersOrdre);
                    }
                    return oListOdr;
                }
            }
            catch (Exception excThrown)
            {
                throw new Exception(excThrown.Message);
            }

        }

提前谢谢您， 史蒂夫

Answer 1

为什么不直接将 csv 中的数据插入到临时表中，然后过滤插入到目标表中的内容以删除重复行。这样你就可以让数据库完成工作，无论如何都会更快。

这是满足您需求的最简单的 SQL

insert into Order
  select * from Order_Temp
  WHERE NOT EXISTS
  (
    SELECT X
    FROM Order o
    WHERE o.NO_ORDRE = Order_Temp.NO_ORDRE
    AND o.CODE_CLIENT = Order_Temp.CODE_CLIENT
  )

希望对你有帮助