SqlDataReader和SqlCommand

Question

我有以下代碼。

using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString)) 
{ 
    connection.Open(); 
    SqlCommand select = new SqlCommand("SELECT RTRIM(LTRIM(PART_NO)) AS PART_NO, record FROM [RMAData].[dbo].[IMPORTING_ORDER_EDI] WHERE sessionID = '" + Session.SessionID + "'", connection); 

    SqlDataReader reader = select.ExecuteReader(); 

    if (reader.HasRows) 
    { 
     while (reader.Read()) 
     { 
     if (!currentPart.IsActive) 
     { 
      // this part is not active, set the active flag in sql to 0 
      SqlCommand update = new SqlCommand("UPDATE [RMAData].[dbo].[IMPORTING_ORDER_EDI] SET valid = 0, active = 0 WHERE record = " + reader["record"].ToString() + ";", connection); 

      update.ExecuteNonQuery(); 
     } 
     else 
     { 
      ///blah 
     } 
     } 

     reader.Close(); 
    } 
} 

但這會導致以下異常...

System.InvalidOperationException：有已與此命令必須先關閉相關聯的打開的DataReader 。

我需要讀取返回的每一行，對數據做一些驗證並在必要時進行更新，然後繼續到下一條記錄。如果我在使用reader.Read()循環時不能使用SqlCommand，我該如何實現這一目標？

Answer 1

另一種是不加MultipleActiveResultSets使用多個連接=真 - 這樣做有一個小的性能損失 - 如此類似 - 例如：

using (SqlConnection connection = new ...)) 
{ 
    connection.Open(); 
    SqlCommand select = new SqlCommand(...); 

    SqlDataReader reader = select.ExecuteReader(); 

    var toInactivate = new List<string>(); 

    if (reader.HasRows) 
    { 
     while (reader.Read()) 
     { 
     if (!currentPart.IsActive) 
     { 
      toInactivate.Add(reader["record"].ToString()); 
     } 
     else 
     { 
      ///blah 
     } 
     } 

     reader.Close(); 
    } 

    SqlCommand update = new SqlCommand("UPDATE ... SET valid = 0, active = 0 " + 
     "WHERE record IN(" + string.Join(",", toInactivate) + ");", connection); 

    update.ExecuteNonQuery(); 
} 

whic h具有在單個SQL語句中更新所有必需記錄的優點。

當然，整個事情會更加整潔，使用EF和Linq。

Answer 2

可能是這麼簡單amending your connection string：

添加MultipleActiveResultSets = True以連接字符串

Answer 3

您需要可以創建你連接的多個實例。
由於只需要一個命令可以對在一個連接中excuted一般
或

做由@grantThomas建議
或者你可以按如下

using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString)) 
{ 
    connection.Open(); 
    SqlCommand select = new SqlCommand("SELECT RTRIM(LTRIM(PART_NO)) AS PART_NO, record FROM [RMAData].[dbo].[IMPORTING_ORDER_EDI] WHERE sessionID = '" + Session.SessionID + "'", connection); 

    SqlDataReader reader = select.ExecuteReader(); 

    if (reader.HasRows) 
    { 
     while (reader.Read()) 
     { 
     if (!currentPart.IsActive) 
     { 
      // this part is not active, set the active flag in sql to 0 
      using (SqlConnection connection1 = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString)) 
      { 
       SqlCommand update = new SqlCommand("UPDATE [RMAData].[dbo].[IMPORTING_ORDER_EDI] SET valid = 0, active = 0 WHERE record = " + reader["record"].ToString() + ";", connection1); 


      update.ExecuteNonQuery(); 
      } 
     } 
     else 
     { 
      ///blah 
     } 
     } 

     reader.Close(); 
    } 
}