myBD::myBD(const QString& bd, QWidget* wid1) : QWidget(wid1)
{
    model = new QSqlTableModel;
    model->setTable(bd);
    model->select();
    model->setEditStrategy(QSqlTableModel::OnFieldChange);
    model->setHeaderData(0, Qt::Horizontal, QObject::tr("ID"));
    model->setHeaderData(1, Qt::Horizontal, QObject::tr("Pole1"));
    model->setHeaderData(2, Qt::Horizontal, QObject::tr("Pole2"));

    QTableView *view = new QTableView;
    view->setModel(model);
    view->setColumnHidden(0, true);
    setWindowTitle(tr("Baza dannih"));

    QPushButton *quitButton = new QPushButton("&Exit");
    QObject::connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
    QHBoxLayout *buttonLayout = new QHBoxLayout;
    buttonLayout->addWidget(quitButton);
    usrName = new QLineEdit;
    usrValue = new QDoubleSpinBox;
    buttonLayout->addWidget(usrName);
    buttonLayout->addWidget(usrValue);

    QPushButton *upd2Button = new QPushButton("&Update");
    QObject::connect(upd2Button, SIGNAL(clicked()), this, SLOT(updateString()));
    buttonLayout->addWidget(upd2Button);

    QVBoxLayout *mainLayout = new QVBoxLayout;
    mainLayout->addWidget(view);mainLayout->addLayout(buttonLayout);
    setLayout(mainLayout);
    resize(600,500);
}

bool myBD::updateString(){
    QSqlQuery query;
    query.prepare("update bdName set Pole1 = ? where Pole2 = ?");
    query.addBindValue(usrValue->text());
    query.addBindValue(usrName->text());
    model->submitAll();
    return query.exec();
}

 ui->tableView->model()->submit();