看例子,有的时候用m_pRecordset->Open((_bstr_t)sql,theApp.m_pConnection.GetInterfacePtr(), adOpenKeyset,adLockPessimistic,adCmdText); 
有的时候用m_pRecordset->Open((_bstr_t)sql,m_pConnection.GetInterfacePtr(), adOpenKeyset,adLockPessimistic,adCmdText); 
请问这是为什么啊