Qt Reference Documentation

# window.cpp Example File

sql/sqlwidgetmapper/window.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** 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 Nokia Corporation and its Subsidiary(-ies) 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 <QtGui>
     #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);
     }