Qt 5.11 | Qt SQL | Relational Table Model Example | relationaltablemodel.cpp Example File

Qt 5.11.3 Reference Documentation

# relationaltablemodel.cpp Example File

relationaltablemodel/relationaltablemodel.cpp

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      #include <QtWidgets>
      #include <QtSql>

      #include "../connection.h"

      void initializeModel(QSqlRelationalTableModel *model)
      {
          model->setTable("employee");

          model->setEditStrategy(QSqlTableModel::OnManualSubmit);
          model->setRelation(2, QSqlRelation("city", "id", "name"));
          model->setRelation(3, QSqlRelation("country", "id", "name"));

          model->setHeaderData(0, Qt::Horizontal, QObject::tr("ID"));
          model->setHeaderData(1, Qt::Horizontal, QObject::tr("Name"));
          model->setHeaderData(2, Qt::Horizontal, QObject::tr("City"));
          model->setHeaderData(3, Qt::Horizontal, QObject::tr("Country"));

          model->select();
      }

      QTableView *createView(const QString &title, QSqlTableModel *model)
      {
          QTableView *view = new QTableView;
          view->setModel(model);
          view->setItemDelegate(new QSqlRelationalDelegate(view));
          view->setWindowTitle(title);
          return view;
      }

      void createRelationalTables()
      {
          QSqlQuery query;
          query.exec("create table employee(id int primary key, name varchar(20), city int, country int)");
          query.exec("insert into employee values(1, 'Espen', 5000, 47)");
          query.exec("insert into employee values(2, 'Harald', 80000, 49)");
          query.exec("insert into employee values(3, 'Sam', 100, 1)");

          query.exec("create table city(id int, name varchar(20))");
          query.exec("insert into city values(100, 'San Jose')");
          query.exec("insert into city values(5000, 'Oslo')");
          query.exec("insert into city values(80000, 'Munich')");

          query.exec("create table country(id int, name varchar(20))");
          query.exec("insert into country values(1, 'USA')");
          query.exec("insert into country values(47, 'Norway')");
          query.exec("insert into country values(49, 'Germany')");
      }

      int main(int argc, char *argv[])
      {
          QApplication app(argc, argv);
          if (!createConnection())
              return EXIT_FAILURE;

          createRelationalTables();

          QSqlRelationalTableModel model;

          initializeModel(&model);

          QScopedPointer<QTableView> view(createView(QObject::tr("Relational Table Model"), &model));
          view->show();

          return app.exec();
      }