OracleLob.Write(Byte[], Int32, Int32) 方法

public:
 override void Write(cli::array <System::Byte> ^ buffer, int offset, int count);

public override void Write(byte[] buffer, int offset, int count);

override this.Write : byte[] * int * int -> unit

Public Overrides Sub Write (buffer As Byte(), offset As Integer, count As Integer)

參數

例外狀況

備註

若寫入成功，串流中的位置會依照寫入的位元組數前進。 若發生例外，串流中的位置保持不變。

允許寫入超過的 LOB 部分，並可 LOB 放大寫入的位元組數。

Oracle 的 .NET Framework Data Provider 以 Unicode 形式處理所有 CLOB 和 NCLOB 資料。 因此，存取 CLOB 資料 NCLOB 型別時，你總是處理位元組數，每個字元為 2 位元組。 例如，若一串包含三個字元的文字串被儲存為 ， NCLOB 且該伺服器的字元集為每個字元為 4 位元組，並執行 Write 操作時，你會指定字串長度為 6 位元組，儘管伺服器上儲存為 12 位元組。

要寫入 LOB，必須先使用 SQL SELECT 陳述句中的 FOR UPDATE 子句取得 ， LOB 並且必須啟動本地交易。

以下範例示範如何寫入物件 OracleLob ：

public static void WriteLobExample(OracleCommand command)
{
    // Note: Updating LOB data requires a transaction.
    command.Transaction = command.Connection.BeginTransaction();
    // Select some data.
    //    Table Schema:
    //        "CREATE TABLE tablewithlobs (a int, b BLOB, c BLOB)";
    //        "INSERT INTO tablewithlobs values (1, 'AA', 'AAA')";
    command.CommandText = "SELECT * FROM TableWithLobs FOR UPDATE";
    OracleDataReader reader = command.ExecuteReader();
    using(reader)
    {
        // Obtain the first row of data.
        reader.Read();
        // Obtain both LOBs.
        OracleLob BLOB1 = reader.GetOracleLob(1);
        OracleLob BLOB2 = reader.GetOracleLob(2);
        // Perform any desired operations on the LOB, (read, position, and so on).
        // ...
        // Example - Writing binary data (directly to the backend).
        // To write, you can use any of the stream classes, or write raw binary data using
        // the OracleLob write method. Writing character vs. binary is the same;
        // however note that character is always in terms of Unicode byte counts
        // (for example: even number of bytes - 2 bytes for every Unicode character).
        var buffer = new byte[100];
        buffer[0] = 0xCC;
        buffer[1] = 0xDD;
        BLOB1.Write(buffer, 0, 2);
        BLOB1.Position = 0;
        Console.WriteLine(BLOB1.LobType + ".Write(" + buffer + ", 0, 2) => " + BLOB1.Value);

        // Example - Copying data into another LOB.
        long actual = BLOB1.CopyTo(BLOB2);
        Console.WriteLine(BLOB1.LobType + ".CopyTo(" + BLOB2.Value + ") => " + actual);

        // Commit the transaction now that everything succeeded.
        // Note: On error, Transaction.Dispose is called (from the using statement)
        // and will automatically roll-back the pending transaction.
        command.Transaction.Commit();
    }
}