window.cpp Example File

  /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** "Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/

  #include <QtWidgets>
  #include <QtSql>

  #include "window.h"

  Window::Window(QWidget *parent)
      : QWidget(parent)
  {
      setupModel();

      nameLabel = new QLabel(tr("Na&me:"));
      nameEdit = new QLineEdit();
      addressLabel = new QLabel(tr("&Address:"));
      addressEdit = new QTextEdit();
      typeLabel = new QLabel(tr("&Type:"));
      typeComboBox = new QComboBox();
      nextButton = new QPushButton(tr("&Next"));
      previousButton = new QPushButton(tr("&Previous"));

      nameLabel->setBuddy(nameEdit);
      addressLabel->setBuddy(addressEdit);
      typeLabel->setBuddy(typeComboBox);

      QSqlTableModel *relModel = model->relationModel(typeIndex);
      typeComboBox->setModel(relModel);
      typeComboBox->setModelColumn(relModel->fieldIndex("description"));

      mapper = new QDataWidgetMapper(this);
      mapper->setModel(model);
      mapper->setItemDelegate(new QSqlRelationalDelegate(this));
      mapper->addMapping(nameEdit, model->fieldIndex("name"));
      mapper->addMapping(addressEdit, model->fieldIndex("address"));
      mapper->addMapping(typeComboBox, typeIndex);

      connect(previousButton, SIGNAL(clicked()),
              mapper, SLOT(toPrevious()));
      connect(nextButton, SIGNAL(clicked()),
              mapper, SLOT(toNext()));
      connect(mapper, SIGNAL(currentIndexChanged(int)),
              this, SLOT(updateButtons(int)));

      QGridLayout *layout = new QGridLayout();
      layout->addWidget(nameLabel, 0, 0, 1, 1);
      layout->addWidget(nameEdit, 0, 1, 1, 1);
      layout->addWidget(previousButton, 0, 2, 1, 1);
      layout->addWidget(addressLabel, 1, 0, 1, 1);
      layout->addWidget(addressEdit, 1, 1, 2, 1);
      layout->addWidget(nextButton, 1, 2, 1, 1);
      layout->addWidget(typeLabel, 3, 0, 1, 1);
      layout->addWidget(typeComboBox, 3, 1, 1, 1);
      setLayout(layout);

      setWindowTitle(tr("SQL Widget Mapper"));
      mapper->toFirst();
  }

  void Window::setupModel()
  {
      QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
      db.setDatabaseName(":memory:");
      if (!db.open()) {
          QMessageBox::critical(0, tr("Cannot open database"),
              tr("Unable to establish a database connection.\n"
                 "This example needs SQLite support. Please read "
                 "the Qt SQL driver documentation for information how "
                 "to build it."), QMessageBox::Cancel);
          return;
      }

      QSqlQuery query;
      query.exec("create table person (id int primary key, "
                 "name varchar(20), address varchar(200), typeid int)");
      query.exec("insert into person values(1, 'Alice', "
                 "'<qt>123 Main Street<br/>Market Town</qt>', 101)");
      query.exec("insert into person values(2, 'Bob', "
                 "'<qt>PO Box 32<br/>Mail Handling Service"
                 "<br/>Service City</qt>', 102)");
      query.exec("insert into person values(3, 'Carol', "
                 "'<qt>The Lighthouse<br/>Remote Island</qt>', 103)");
      query.exec("insert into person values(4, 'Donald', "
                 "'<qt>47338 Park Avenue<br/>Big City</qt>', 101)");
      query.exec("insert into person values(5, 'Emma', "
                 "'<qt>Research Station<br/>Base Camp<br/>"
                 "Big Mountain</qt>', 103)");

      query.exec("create table addresstype (id int, description varchar(20))");
      query.exec("insert into addresstype values(101, 'Home')");
      query.exec("insert into addresstype values(102, 'Work')");
      query.exec("insert into addresstype values(103, 'Other')");

      model = new QSqlRelationalTableModel(this);
      model->setTable("person");
      model->setEditStrategy(QSqlTableModel::OnManualSubmit);

      typeIndex = model->fieldIndex("typeid");

      model->setRelation(typeIndex,
             QSqlRelation("addresstype", "id", "description"));
      model->select();
  }

  void Window::updateButtons(int row)
  {
      previousButton->setEnabled(row > 0);
      nextButton->setEnabled(row < model->rowCount() - 1);
  }