Visual C++ .NET/Database ADO.net/Blob

Deal with Blob

 
#include "stdafx.h"
using namespace System;
using namespace System::Data;
using namespace System::IO;
using namespace System::Data::OleDb;
void main()
{
    OleDbConnection^ myConnection = nullptr;
    myConnection = gcnew OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Music.mdb");
    myConnection->Open();
    OleDbCommand^ myCommand = gcnew OleDbCommand("SELECT FileName, MP3 FROM MP3Storage", myConnection);
    OleDbDataReader^ myReader = myCommand->ExecuteReader(CommandBehavior::SequentialAccess);
    array<unsigned char>^ buffer = gcnew array<unsigned char>(65536);
    while ( myReader->Read() ){
       String^ fileName = safe_cast<String^>(myReader->GetValue(0));
       FileStream^ fileStream = gcnew FileStream(fileName, FileMode::Create);
       long long bytesRead, position = 0;
       while ( bytesRead = myReader->GetBytes(1, position, buffer,0, buffer->Length) ){
          fileStream->Write(buffer, 0, (int)bytesRead);
          position += bytesRead;
       }
       Console::WriteLine("{0} bytes writte to {1} file",position, fileName);
       fileStream->Close();
    }
    myConnection->Close();
}