VC++用ADO连接数据库，登陆界面代码怎么写？

VC++用ADO连接数据库，登陆界面代码怎么写？在线等，急，高分
C++新手，要详细注释！谢谢啊！

1.提取单条记录

CoInitialize(NULL);
_bstr_t varSource="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=%%0"; /
CoInitialize(NULL);
_bstr_t varSource="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=%%0"; /
_ConnectionPtr Conn = NULL;
_RecordsetPtr Rs = NULL;
_CommandPtr Cmd = NULL;
CoInitialize(NULL);
Conn.CreateInstance (_uuidof(Connection));
Rs.CreateInstance (_uuidof(Recordset));
Cmd.CreateInstance (_uuidof(Command));
Conn->Open(L"db", L"sa", L"", adOpenUnspecified); //打开正常
//如下为_CommandPtr对象参数的赋值和调用
Cmd->ActiveConnection = Conn;
Cmd->CommandText = "SP_TEST";
//数据库中实际存在这个测试存储过程，select * from atable,不传递参数
Cmd->CommandType = adCmdStoredProc;
Cmd->Parameters->Refresh();
Rs = Cmd->Execute( NULL,NULL, adCmdUnknown ); //COM出错。
//注释掉的代码为直接的SQL语句提交，运行正确。
//Cmd->ActiveConnection=Conn;
//Cmd->CommandText = "select * from atable";
//Cmd->CommandType = adCmdText;
//Cmd->Parameters->Refresh();
//Rs = Cmd->Execute(NULL,NULL,adCmdUnknown);
Rs->Close();
Conn->Close();
CoUninitialize();