browser.cpp Example File

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  #include "browser.h"
  #include "qsqlconnectiondialog.h"

  #include <QtWidgets>
  #include <QtSql>

  Browser::Browser(QWidget *parent)
      : QWidget(parent)
  {
      setupUi(this);

      table->addAction(insertRowAction);
      table->addAction(deleteRowAction);
      table->addAction(fieldStrategyAction);
      table->addAction(rowStrategyAction);
      table->addAction(manualStrategyAction);
      table->addAction(submitAction);
      table->addAction(revertAction);
      table->addAction(selectAction);

      if (QSqlDatabase::drivers().isEmpty())
          QMessageBox::information(this, tr("No database drivers found"),
                                   tr("This demo requires at least one Qt database driver. "
                                      "Please check the documentation how to build the "
                                      "Qt SQL plugins."));

      emit statusMessage(tr("Ready."));
  }

  Browser::~Browser()
  {
  }

  void Browser::exec()
  {
      QSqlQueryModel *model = new QSqlQueryModel(table);
      model->setQuery(QSqlQuery(sqlEdit->toPlainText(), connectionWidget->currentDatabase()));
      table->setModel(model);

      if (model->lastError().type() != QSqlError::NoError)
          emit statusMessage(model->lastError().text());
      else if (model->query().isSelect())
          emit statusMessage(tr("Query OK."));
      else
          emit statusMessage(tr("Query OK, number of affected rows: %1").arg(
                             model->query().numRowsAffected()));

      updateActions();
  }

  QSqlError Browser::addConnection(const QString &driver, const QString &dbName, const QString &host,
                              const QString &user, const QString &passwd, int port)
  {
      static int cCount = 0;

      QSqlError err;
      QSqlDatabase db = QSqlDatabase::addDatabase(driver, QString("Browser%1").arg(++cCount));
      db.setDatabaseName(dbName);
      db.setHostName(host);
      db.setPort(port);
      if (!db.open(user, passwd)) {
          err = db.lastError();
          db = QSqlDatabase();
          QSqlDatabase::removeDatabase(QString("Browser%1").arg(cCount));
      }
      connectionWidget->refresh();

      return err;
  }

  void Browser::addConnection()
  {
      QSqlConnectionDialog dialog(this);
      if (dialog.exec() != QDialog::Accepted)
          return;

      if (dialog.useInMemoryDatabase()) {
          QSqlDatabase::database("in_mem_db", false).close();
          QSqlDatabase::removeDatabase("in_mem_db");
          QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE", "in_mem_db");
          db.setDatabaseName(":memory:");
          if (!db.open())
              QMessageBox::warning(this, tr("Unable to open database"), tr("An error occurred while "
                                                                           "opening the connection: ") + db.lastError().text());
          QSqlQuery q("", db);
          q.exec("drop table Movies");
          q.exec("drop table Names");
          q.exec("create table Movies (id integer primary key, Title varchar, Director varchar, Rating number)");
          q.exec("insert into Movies values (0, 'Metropolis', 'Fritz Lang', '8.4')");
          q.exec("insert into Movies values (1, 'Nosferatu, eine Symphonie des Grauens', 'F.W. Murnau', '8.1')");
          q.exec("insert into Movies values (2, 'Bis ans Ende der Welt', 'Wim Wenders', '6.5')");
          q.exec("insert into Movies values (3, 'Hardware', 'Richard Stanley', '5.2')");
          q.exec("insert into Movies values (4, 'Mitchell', 'Andrew V. McLaglen', '2.1')");
          q.exec("create table Names (id integer primary key, Firstname varchar, Lastname varchar, City varchar)");
          q.exec("insert into Names values (0, 'Sala', 'Palmer', 'Morristown')");
          q.exec("insert into Names values (1, 'Christopher', 'Walker', 'Morristown')");
          q.exec("insert into Names values (2, 'Donald', 'Duck', 'Andeby')");
          q.exec("insert into Names values (3, 'Buck', 'Rogers', 'Paris')");
          q.exec("insert into Names values (4, 'Sherlock', 'Holmes', 'London')");
          connectionWidget->refresh();
      } else {
          QSqlError err = addConnection(dialog.driverName(), dialog.databaseName(), dialog.hostName(),
                             dialog.userName(), dialog.password(), dialog.port());
          if (err.type() != QSqlError::NoError)
              QMessageBox::warning(this, tr("Unable to open database"), tr("An error occurred while "
                                         "opening the connection: ") + err.text());
      }
  }

  void Browser::showTable(const QString &t)
  {
      QSqlTableModel *model = new CustomModel(table, connectionWidget->currentDatabase());
      model->setEditStrategy(QSqlTableModel::OnRowChange);
      model->setTable(connectionWidget->currentDatabase().driver()->escapeIdentifier(t, QSqlDriver::TableName));
      model->select();
      if (model->lastError().type() != QSqlError::NoError)
          emit statusMessage(model->lastError().text());

      table->setModel(model);
      table->setEditTriggers(QAbstractItemView::DoubleClicked|QAbstractItemView::EditKeyPressed);
      connect(table->selectionModel(), &QItemSelectionModel::currentRowChanged,
              this, &Browser::currentChanged);

      updateActions();
  }

  void Browser::showMetaData(const QString &t)
  {
      QSqlRecord rec = connectionWidget->currentDatabase().record(t);
      QStandardItemModel *model = new QStandardItemModel(table);

      model->insertRows(0, rec.count());
      model->insertColumns(0, 7);

      model->setHeaderData(0, Qt::Horizontal, "Fieldname");
      model->setHeaderData(1, Qt::Horizontal, "Type");
      model->setHeaderData(2, Qt::Horizontal, "Length");
      model->setHeaderData(3, Qt::Horizontal, "Precision");
      model->setHeaderData(4, Qt::Horizontal, "Required");
      model->setHeaderData(5, Qt::Horizontal, "AutoValue");
      model->setHeaderData(6, Qt::Horizontal, "DefaultValue");

      for (int i = 0; i < rec.count(); ++i) {
          QSqlField fld = rec.field(i);
          model->setData(model->index(i, 0), fld.name());
          model->setData(model->index(i, 1), fld.typeID() == -1
                  ? QString(QMetaType::typeName(fld.type()))
                  : QString("%1 (%2)").arg(QMetaType::typeName(fld.type())).arg(fld.typeID()));
          model->setData(model->index(i, 2), fld.length());
          model->setData(model->index(i, 3), fld.precision());
          model->setData(model->index(i, 4), fld.requiredStatus() == -1 ? QVariant("?")
                  : QVariant(bool(fld.requiredStatus())));
          model->setData(model->index(i, 5), fld.isAutoValue());
          model->setData(model->index(i, 6), fld.defaultValue());
      }

      table->setModel(model);
      table->setEditTriggers(QAbstractItemView::NoEditTriggers);

      updateActions();
  }

  void Browser::insertRow()
  {
      QSqlTableModel *model = qobject_cast<QSqlTableModel *>(table->model());
      if (!model)
          return;

      QModelIndex insertIndex = table->currentIndex();
      int row = insertIndex.row() == -1 ? 0 : insertIndex.row();
      model->insertRow(row);
      insertIndex = model->index(row, 0);
      table->setCurrentIndex(insertIndex);
      table->edit(insertIndex);
  }

  void Browser::deleteRow()
  {
      QSqlTableModel *model = qobject_cast<QSqlTableModel *>(table->model());
      if (!model)
          return;

      QModelIndexList currentSelection = table->selectionModel()->selectedIndexes();
      for (int i = 0; i < currentSelection.count(); ++i) {
          if (currentSelection.at(i).column() != 0)
              continue;
          model->removeRow(currentSelection.at(i).row());
      }

      updateActions();
  }

  void Browser::updateActions()
  {
      QSqlTableModel * tm = qobject_cast<QSqlTableModel *>(table->model());
      bool enableIns = tm;
      bool enableDel = enableIns && table->currentIndex().isValid();

      insertRowAction->setEnabled(enableIns);
      deleteRowAction->setEnabled(enableDel);

      fieldStrategyAction->setEnabled(tm);
      rowStrategyAction->setEnabled(tm);
      manualStrategyAction->setEnabled(tm);
      submitAction->setEnabled(tm);
      revertAction->setEnabled(tm);
      selectAction->setEnabled(tm);

      if (tm) {
          QSqlTableModel::EditStrategy es = tm->editStrategy();
          fieldStrategyAction->setChecked(es == QSqlTableModel::OnFieldChange);
          rowStrategyAction->setChecked(es == QSqlTableModel::OnRowChange);
          manualStrategyAction->setChecked(es == QSqlTableModel::OnManualSubmit);
      }
  }

  void Browser::about()
  {
      QMessageBox::about(this, tr("About"), tr("The SQL Browser demonstration "
          "shows how a data browser can be used to visualize the results of SQL"
                                               "statements on a live database"));
  }

  void Browser::on_fieldStrategyAction_triggered()
  {
      QSqlTableModel * tm = qobject_cast<QSqlTableModel *>(table->model());
      if (tm)
          tm->setEditStrategy(QSqlTableModel::OnFieldChange);
  }

  void Browser::on_rowStrategyAction_triggered()
  {
      QSqlTableModel * tm = qobject_cast<QSqlTableModel *>(table->model());
      if (tm)
          tm->setEditStrategy(QSqlTableModel::OnRowChange);
  }

  void Browser::on_manualStrategyAction_triggered()
  {
      QSqlTableModel * tm = qobject_cast<QSqlTableModel *>(table->model());
      if (tm)
          tm->setEditStrategy(QSqlTableModel::OnManualSubmit);
  }

  void Browser::on_submitAction_triggered()
  {
      QSqlTableModel * tm = qobject_cast<QSqlTableModel *>(table->model());
      if (tm)
          tm->submitAll();
  }

  void Browser::on_revertAction_triggered()
  {
      QSqlTableModel * tm = qobject_cast<QSqlTableModel *>(table->model());
      if (tm)
          tm->revertAll();
  }

  void Browser::on_selectAction_triggered()
  {
      QSqlTableModel * tm = qobject_cast<QSqlTableModel *>(table->model());
      if (tm)
          tm->select();
  }