Attributes error

Dear Developers

I've written in vc++7 following codes

//******************************************
HRESULT hr = S_OK;
TCHAR szAuthor[80];

[db_command(name="cmd", source_name="GetDocument()->m_MyProjectSet", hresult=hr)
{
SELECT au_lname
([bindto]szAuthor)
FROM AUTHORS
}];

while(cmd.MoveNext() == S_OK)
m_DataList.InsertString(-1, szAuthor);
//******************************************

As you see I've used "db_command" attribute but compiler shows

"error C2065: 'cmd' : undeclared identifier"

could you please inform me why this happens.

Regards