the second example in Detailed Description for QSqlTableModel has nothing to do with it

the second example in Detailed Description
here http://qt-project.org/doc/qt-5.0/qtsql/qsqltablemodel.html
for QSqlTableModel has nothing to do with it .
the example is about QSqlQueryModel not QSqlTableModel.
you can change it to

QSqlTableModel model;
model.select();
int salary = model.record(4).value("salary").toInt();