ADO 连接数据库的问题

C/C++ code

try    {        CoInitialize(NULL);        _ConnectionPtr  m_pConnection;        m_pConnection.CreateInstance(__uuidof(_Connection));        m_pConnection->ConnectionString = "Provider=SQLOLEDB.1;Password=qxd5024278;Persist Security Info=False;User ID=qxd;Data Source=QIN-PC\SQLEXPRESS";        m_pConnection->Open("","","",NULL);    }    catch(_com_error e)       {           CString str = e.ErrorMessage();          MessageBox(str);    }

然后提示无效指针。
小弟新手求各位大牛帮忙

[解决办法]
LZ这个发到对应的版块，答案会来的快些.
[解决办法]
m_pConnection->ConnectionString = "Provider=SQLOLEDB.1;Password=qxd5024278;Persist Security Info=False;User ID=qxd;Data Source=QIN-PC\SQLEXPRESS";

没有写连接到的数据库名