Saving an ADO Recordset to an IStream

int main(int argc, char* argv[])
{
	InitOle oleinit;

	HRESULT hr=S_OK;
	_RecordsetPtr rs; //Recordset for Saving Data
	_RecordsetPtr rs2; //Recordset for Loading Data
	IStreamPtr pStream;

//----------------------------------------
//	Create a recordset for testing
//----------------------------------------
	if (FAILED(CreateTestRS(&rs)))
	{
		printf("Couldn't create the first recordset\n");
		goto exit;
	}

//----------------------------------------
//	Create IStream
//----------------------------------------
	if (FAILED(SaveRS(rs, (IStream**)&pStream)))
	{
		printf("Couldn't save the recordset\n");
		goto exit;
	}

//----------------------------------------
//	Load another recordset from IStream
//----------------------------------------
	if (FAILED(LoadRS(&rs2, pStream)))
	{
		printf("Couldn't save the recordset\n");
		goto exit;
	}
	//Now display the names of the fields of the rs that we just recreated
	{
		for (short i =0;i<rs2->Fields->Count;i++)
		printf("Name of field %d is %s\n", i, (LPCTSTR) rs2->Fields->GetItem(i)->Name);
	}



//----------------------------------------
//	Pause and then exit so that the user
//	Can  
//----------------------------------------

exit:
	printf("Press any key to end program\n");
	_getch();
	return 0;
}


//----------------------------------------
//	Create a recordset from scratch
//----------------------------------------

HRESULT CreateTestRS(_Recordset** prs/*OUT*/)
{
    try
    {
	* prs=NULL;
	_RecordsetPtr pRS;
	pRS.CreateInstance( __uuidof(Recordset));
	pRS->CursorLocation = adUseClient;
	pRS->CursorType = adOpenStatic;
	pRS->LockType = adLockBatchOptimistic;
	// append fields
	pRS->Fields->Append(_bstr_t("ADOField1"), adVarChar, 45,adFldFixed);
	pRS->Fields->Append(_bstr_t("ADOField2"), adBoolean, 0,adFldFixed);
	pRS->Fields->Append(_bstr_t("ADOField3"), adCurrency, 0,adFldFixed);
	pRS->Fields->Append(_bstr_t("ADOField4"), adDate, 0,adFldFixed);
	pRS->Open(vtMissing, vtMissing, adOpenStatic,adLockBatchOptimistic,-1);
	*prs= pRS.Detach();
    }
    catch (_com_error & e)
    {
	return e.Error();
    }
    return S_OK;
}

HRESULT SaveRS(_RecordsetPtr pRS/*IN*/, IStream* * ppStream/*OUT*/)
{
    HRESULT hr=S_OK;
    try
    {
	*ppStream=NULL;

        // QI and return IPersistStream
        IPersistStreamPtr pIPersist(pRS);
        if (pIPersist )
        {
            //Create a standard stream in memory
            if (FAILED(hr=CreateStreamOnHGlobal(0, TRUE, (IStream **)ppStream)))
		return hr;

            // Persist the pRS
            if (FAILED(hr=OleSaveToStream(pIPersist, *ppStream)))
		return hr;

        }
        else
            return E_NOINTERFACE;
    }
    catch (_com_error & e)
    {
	return e.Error();
    }
return S_OK;
    
}

HRESULT LoadRS(_Recordset* *ppRS/*OUT*/, IStreamPtr pStream/*IN*/)
{
    HRESULT hr=S_OK;
    try
    {
	*ppRS=NULL;
        if (NULL==pStream)
            return E_NOINTERFACE;
        // Load the pRS.
        LARGE_INTEGER li;
        li.QuadPart = 0;

	//Set the pointer to the beginning of the stream
        if (FAILED(hr=pStream->Seek(li, STREAM_SEEK_SET, 0)))
            return hr;

	if (FAILED(hr=OleLoadFromStream(pStream, 
        	__uuidof(_Recordset),
                reinterpret_cast<LPVOID *>(ppRS)))
		)
            return hr;
    }
    catch (_com_error & e)
    {
	return e.Error();
    }
    return S_OK;
}