It doesn't give any errors but when I debug my code, at while(readPassword.next()) step nothing happens. I'm pretty sure that the database contains passwords and usernames. There is nothing wrong with the code because it works on Linux. And in this directory "C:\Qt\2010.05\qt\plugins\sqldrivers" qsqlite4.dll, qsqlited4.dll, qsqlodbc4.dll, qsqlodbcd4.dll files exist.