#include <QtSql/qsqlrelationaltablemodel.h>
#ifndef QSQLRELATIONALTABLEMODEL_H
class QSqlRelationalTableModel: public QSqlTableModel{
   /* Some contents are skipped to improve readability */
   public: virtual class QSqlTableModel* relationModel(int column) const
   /* ... */
};
#endif // QSQLRELATIONALTABLEMODEL_H