Qt的模型/视图架构

Question

在与数据库建立连接后，我编写了以下代码，但在执行后，内部单元格为空。为什么呢？

enum {
        name = 0,
        clas = 1,
        launched = 2
    };

      QSqlTableModel* model = new QSqlTableModel;
       model->setTable("ships");
       model->setSort(name, Qt::AscendingOrder);
       model->setHeaderData(name, Qt::Horizontal, "Name");
       model->setHeaderData(clas, Qt::Horizontal, "class");
       model->setHeaderData(launched, Qt::Horizontal, "launched");

       model->select();   

     QTableView *  view = new QTableView;   

           view->setModel(model);
           view->setSelectionMode(QAbstractItemView::SingleSelection);
           view->setSelectionBehavior(QAbstractItemView::SelectRows);
           view->resizeColumnsToContents();
           view->setEditTriggers(QAbstractItemView::NoEditTriggers);
           QHeaderView *header = view->horizontalHeader();
           header->setStretchLastSection(true);
           view->show();