ODP.NET無法從數據讀取器讀取數據

Question

我是Oracle新手，試圖從Oracle數據庫中獲取數據。以下是我的代碼。控制檯中沒有顯示錯誤。但是在代碼中不會進入while循環。因爲我對這個人不熟悉，請幫我解決這個問題？

public void Login() 
     { 
      using (OracleConnection connection = new OracleConnection()) 
      { 
       connection.ConnectionString = ConnectionString; 

       try 
       { 
        LogManager.Info("inside login"); 
        connection.Open(); 
        OracleCommand cmd = connection.CreateCommand(); 
        cmd.Connection = connection; 

        string sql = "select ID from APRV_EMPLOYEE where USERNAME = :username "; 
        LogManager.Info("sql" + sql); 
        cmd.CommandType = CommandType.Text; 
        cmd.CommandText = sql; 
        cmd.BindByName = true; 
        cmd.Parameters.Add(":username", OracleDbType.NVarchar2).Value = "admin"; 
        IDataReader reader = cmd.ExecuteReader(); 

        LogManager.Info("Inside DatabaseManager::hasrows"); 
        while (reader.Read()) 
        { 
         LogManager.Info("Inside DatabaseManager::read" + reader.GetString(1)); 
         LogManager.Info("Inside DatabaseManager::read2" + reader.GetString(reader.GetOrdinal("ID"))); 

        } 

        reader.Dispose(); 
        cmd.Dispose(); 
       } 
       catch (Exception ex) 
       { 
        LogManager.Error("Inside DatabaseManager::Login " + ex.Message); 
       } 
      } 
     } 

請幫我提前

Answer 1

感謝望着docs，這裏是它如何工作

string sql = "select ID from APRV_EMPLOYEE where USERNAME = :1 "; 
LogManager.Info("sql" + sql); 
cmd.CommandType = CommandType.Text; 
cmd.CommandText = sql; 
// cmd.BindByName = true; 
cmd.Parameters.Add("username", OracleDbType.NVarchar2).Value = "admin"; 
IDataReader reader = cmd.ExecuteReader();