I have some trouble when I want to add a database.
_dataBase = QSqlDatabase::addDatabase("QPSQL");
QSqlDatabase: QPSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7
Add the system variable QT_DEBUG_PLUGINS=1 if you want to get full information of why the QPSQL driver has not been loaded.
Probably you will discover that Qt is not able to find it. Copy and paste the output here to know what exactly happens.