背景：1.前臺：JQUERY 提交資料

           2.後臺：OWIN C#  處理接收資料

　　　3.資料庫： postgresql

============================================

問題描述：  後臺接收到前臺的資料，拼裝一個 SQL 語句

update wbs_data 
set work_data='{"proName":"科研GOOD","proCode":"科研專案001","unitProName":"No1","drawingNo":"734116","proAddress":"大慶",
                 "partsComponents":"讓胡路鍋底",
                 "checkContent":"<p><br/>       這是一測試圖片<img src=\"/upload/8096b2b7d0a20cf4cd425f7a7f094b36adaf995e.jpg\" alt=\"\" 
                 width=\"200\" height=\"200\" /> <br/></p>",
                 "checkOpinion":"檢查意見：<br/>1.好<br/>2.很好<br/>3.非 常好","materialDocs":"原材料質量檔案：<br/>1.測試檔案1<br/>2.測試檔案2",
                 "monitor":"","deputy":"","superEngineer":"","techLeader":"","date1":"","date2":"","date3":""}',work_state=1 
where pwbs_id=124

 我在後臺C# 用 Npgsql

public static string executeSQL(string strSQL)
        {
            Console.WriteLine("{0}", strSQL);
            string returnValue = string.Empty;
            NpgsqlConnection connection = new NpgsqlConnection(getConnectionString());
            NpgsqlCommand command = new NpgsqlCommand();
            command.Connection = connection;
            command.CommandText = strSQL;
            try
            {
                connection.Open();
                command.ExecuteNonQuery();
                //returnValue = "{\"SUCCESS\":\"執行操作：'" + strSQL + "'成功！\"}";
                Console.WriteLine("{0}","--------------------you are lucky----------------");
                returnValue = "{\"SUCCESS\":\"操作成功！\"}";

            }
            catch (Exception err)
            {
                returnValue = "{\"ERROR\":\"發生以下錯誤：" + err.Message.ToString() + "\"}";
            }
            finally
            {
                connection.Close();
            }
            return returnValue;
        }

 執行時總是報錯：invalid input syntax for type  json

奇怪的是，當我把這個拼裝的SQL語句放在後臺服務上PSQL 執行時，居然還通過了！

why??????