語言

OracleDataReader.GetOrdinal(String) 方法

定義

命名空間:
System.Data.OracleClient
組件:
System.Data.OracleClient.dll

取得資料列序數，指定資料行的名稱。

public:
 virtual int GetOrdinal(System::String ^ name);
public:
 override int GetOrdinal(System::String ^ name);
public int GetOrdinal(string name);
public override int GetOrdinal(string name);
abstract member GetOrdinal : string -> int
override this.GetOrdinal : string -> int
override this.GetOrdinal : string -> int
Public Function GetOrdinal (name As String) As Integer
Public Overrides Function GetOrdinal (name As String) As Integer

參數

name
String

欄位名稱。

傳回

Int32

零基列序數。

實作

GetOrdinal(String)

範例

以下範例示範如何使用此 GetOrdinal 方法。

Public Sub ReadOracleData(ByVal connectionString As String)

    Dim queryString As String = "SELECT OrderID, CustomerID FROM Orders"
    Dim connection As New OracleConnection(connectionString)
    Dim command As New OracleCommand(queryString, connectionString)

    connection.Open()

    Dim reader As OracleDataReader = command.ExecuteReader()

    Dim custIdCol As Integer = reader.GetOrdinal("CustomerID")

    Do While reader.Read()
        Console.WriteLine("CustomerID = {0}", reader.GetString(custIdCol))
    Loop

    reader.Close()
    connection.Close()
End Sub

public void ReadOracleData(string connectionString)
{
    string queryString = "SELECT OrderID, CustomerID FROM Orders";
    OracleConnection connection = new OracleConnection(connectionString);
    OracleCommand command = new OracleCommand(queryString,connection);

    connection.Open();
    OracleDataReader reader = command.ExecuteReader();

    int custIdCol = reader.GetOrdinal("CustomerID");

    while (reader.Read())
        Console.WriteLine("CustomerID = {0}", reader.GetString(custIdCol));

    reader.Close();
    connection.Close();
}

備註

GetOrdinal 先執行大小寫區分查詢。 若失敗，則進行第二次不區寫搜尋。 若找不到以零為基礎的列序數，該方法會 IndexOutOfRange 拋出例外。

GetOrdinal 假名寬度不敏感。

由於基於序數的查詢比命名查詢更有效率，因此在迴圈內呼叫 GetOrdinal 效率較低。 相反地，先呼叫 GetOrdinal 一次，然後將結果指派到一個整數變數，以便在迴圈中使用。

適用於