VC++ 使用ADO操作数据库

Connection15Ptr pConnection;
pConnection.CreateInstance("ADODB.Connection");

_bstr_t bstr_Connectionstring;
bstr_Connectionstring = SysAllocString(L"Provider=SQLOLEDB.1;Password=sa;Persist Security Info=True;User ID=sa;Initial Catalog=Northwind;Data Source=.");

pConnection->Open(bstr_Connectionstring,_bstr_t(""),_bstr_t(""),adConnectUnspecified );
pConnection->Close();

Recordset15Ptr pRecordset;
pRecordset.CreateInstance("ADODB.Recordset");

VARIANT vtRecord;
vtRecord.vt = VT_I4;

BSTR bstr_CommandText = SysAllocString(L"SELECT * FROM dbo.Employees");
pRecordset  = pConnection->Execute(bstr_CommandText,&vtRecord,adCmdText );

while(!pRecordset->AdoEOF)
{
OutputDebugString( (char*) ((_bstr_t) pRecordset->Fields->Item["FirstName"]->Value));
OutputDebugString("\n");
pRecordset->MoveNext();

}
pRecordset->Close();