c# – 如何将unicode数据保存到oracle？

alt text http://i25.tinypic.com/dvpqnk.png

我知道NVARCHAR2总是使用UTF-16编码,所以它必须适用于所有(人类)语言.

然后我试图在数据库中插入一个字符串.我在代码中硬编码了字符串(“你好吗？”).然后我尝试从数据库中恢复并显示它.

class Program
{
    static string connectionString = "<my connection string>";

    static void Main (string[] args) {
        string textBefore = "Τι κ?νει?;";

        DeleteAll ();
        SaveToDatabase (textBefore);
        string textAfter = GetFromDatabase ();

        string beforeData = String.Format ("Before: {0},({1})",textBefore,ToHex (textBefore));
        string afterData = String.Format ("After: {0},textAfter,ToHex (textAfter));

        Console.WriteLine (beforeData);
        Console.WriteLine (afterData);

        MessageBox.Show (beforeData);
        MessageBox.Show (afterData);

        Console.ReadLine ();
    }

    static void DeleteAll () {
        using (var oraConnection = new OracleConnection (connectionString)) {
            oraConnection.Open ();
            var command = oraConnection.CreateCommand ();

            command.CommandText = "delete from UNICODEDATA";
            command.ExecuteNonQuery ();
        }            
    }

    static void SaveToDatabase (string stringToSave) {
        using (var oraConnection = new OracleConnection (connectionString)) {
            oraConnection.Open ();
            var command = oraConnection.CreateCommand ();

            command.CommandText = "INSERT into UNICODEDATA (ID,UNICODESTRING) Values (11,:UnicodeString)";
            command.Parameters.Add (":UnicodeString",stringToSave);
            command.ExecuteNonQuery ();
        }
    }

    static string GetFromDatabase () {
        using (var oraConnection = new OracleConnection (connectionString)) {
            oraConnection.Open ();

            var command = oraConnection.CreateCommand ();
            command.CommandText = "Select * from UNICODEDATA";
            var erpReader = command.ExecuteReader ();

            string s = String.Empty;
            while (erpReader.Read ()) {
                string text = erpReader.GetString (1);
                s += text + ",";
            }

            return s;
        }
    }

    static string ToHex (string input) {
        string bytes = String.Empty;
        foreach (var c in input)
            bytes += ((int)c).ToString ("X4") + " ";

        return bytes;
    }
}

以下是不同的输出：

在消息框中发送到数据库之前的文本：
alt text http://i31.tinypic.com/2ymdo2u.png

从消息框中的数据库获取后的文本：
alt text http://i28.tinypic.com/2wmq9a0.png

控制台输出：
alt text http://i29.tinypic.com/6xz3px.png

请问你能告诉我这里可能做错了什么吗？