How to save the changes database via QSqlTableModel?

I changed the value of cell in my Table:

QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName("sqlite.db");
db.open();

QSqlTableModel *model = new QSqlTableModel(0, db);
model->setTable("Expenses");
model->select();
model->setData(model->index(0,2), 100);

How now to save the changes in the database (sqlite.db)?