OracleDataReader.Read メソッド

定義

OracleDataReader を次のレコードに進めます。Advances the OracleDataReader to the next record.

public:
 virtual bool Read();
public:
 override bool Read();
public bool Read ();
public override bool Read ();
abstract member Read : unit -> bool
override this.Read : unit -> bool
override this.Read : unit -> bool
Public Function Read () As Boolean
Public Overrides Function Read () As Boolean

戻り値

Boolean

次の行が存在する場合は true。それ以外の場合は falsetrue if there are more rows; otherwise, false.

実装

次の例では、、、およびを作成し OracleConnection OracleCommand OracleDataReader ます。The following example creates an OracleConnection, an OracleCommand, and an OracleDataReader. この例では、データを読み取り、コンソールに書き込みます。The example reads through the data, writing it out to the console. 最後に、この例では、を閉じて OracleDataReader から、を閉じ OracleConnection ます。Finally, the example closes the OracleDataReader, then the OracleConnection.

private static void ReadData(string connectionString)
{
    string queryString = "SELECT OrderID, CustomerID FROM Orders";
    using (OracleConnection connection = new OracleConnection(connectionString))
    {
        OracleCommand command = new OracleCommand(queryString, connection);
        connection.Open();
        OracleDataReader reader;
        reader = command.ExecuteReader();

        // Always call Read before accessing data.
        while (reader.Read())
        {
            Console.WriteLine(reader.GetInt32(0) + ", " + reader.GetString(1));
        }

        // Always call Close when done reading.
        reader.Close();
    }
}
Public Sub ReadData(ByVal connectionString As String)
    Dim queryString As String = _
        "SELECT OrderID, CustomerID FROM Orders"

    Using connection As New OracleConnection(connectionString)
        Dim command As New OracleCommand(queryString, connection)
        connection.Open()

        Dim reader As OracleDataReader
        reader = command.ExecuteReader()

        ' Always call Read before accessing data.
        While reader.Read()
            Console.WriteLine(reader.GetInt32(0) & ", " & reader.GetString(1))
        End While

        ' Always call Close when done reading.
        reader.Close()
    End Using
End Sub

注釈

OracleDataReader の既定の位置は、最初のレコードよりも前になります。The default position of the OracleDataReader is prior to the first record. そのため、すべての Read データへのアクセスを開始するには、を呼び出す必要があります。Therefore, you must call Read to begin accessing any data.

OracleDataReader任意の時点で、複数のを開くことができます。More than one OracleDataReader can be open at any given time.

適用対象