Unsolved SQL relational table update

[Dan3460]

I'm learning to use qt and sql. I tested a very similar program with QSqlTableModel and I can edit the data directly from the table view in the dialog. When I use QSqlRelationalTableView, which inherits QSqlTableModel the changes on the table are not transfer to the database. Is there a command to give to update the database?
I'm just playing with this now but eventually I will be building an application where I can add and modify certain data from the application.

Dialog::Dialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::Dialog)
{
ui->setupUi(this);

db = QSqlDatabase::addDatabase("QMYSQL");

db.setHostName("192.168.1.14");
db.setDatabaseName("Radio");
db.setUserName("aaaaa");
db.setPassword("bbbbb");

if(db.open()==false)
{
    QMessageBox::warning(this,"Error","Coudl not Open Database");
}

model = new QSqlRelationalTableModel(this);
model->setTable("Brand");
model->setRelation(7,QSqlRelation("Poster","idPoster","posterName"));
model->select();
ui->tableView->setModel(model);

}