Convert python to Qt c++

[panoss]

This is the code I ended up with (from the QSqlRelationalDelegate 's code), and works!
Any comments are welcome.

    int positionColumn = 2;
    qDebug()<< "BookDelegate.createEditor index.column()=" << (index.column()) << " option=" << option ;
    if (index.column() == positionColumn){
        const QSqlRelationalTableModel *sqlModel = qobject_cast<const QSqlRelationalTableModel *>(index.model());
        QSqlTableModel *childModel = sqlModel ? sqlModel->relationModel(index.column()) : nullptr;
        if (!childModel)
            return QStyledItemDelegate::createEditor(parent, option, index);

        QComboBox *combo = new QComboBox(parent);
        combo->setModel(childModel);
        combo->setModelColumn(1);
        combo->installEventFilter(const_cast<BookDelegate *>(this));
        childModel->select();
        return combo;
    }