Qt 4.0: browser.cpp Example File (demos/sqlbrowser/browser.cpp)

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# browser.cpp Example File
demos/sqlbrowser/browser.cpp

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        **
        ** Copyright (C) 1992-2005 Trolltech AS. All rights reserved.
        **
        ** This file is part of the documentation of the Qt Toolkit.
        **
        ** This file may be used under the terms of the GNU General Public
    ** License version 2.0 as published by the Free Software Foundation
    ** and appearing in the file LICENSE.GPL included in the packaging of
    ** this file.  Please review the following information to ensure GNU
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    ** review the following information:
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        **
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        ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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        #include "browser.h"
        #include "qsqlconnectiondialog.h"

        #include <QtGui>
        #include <QtSql>

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

            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."));
            else {
                QMetaObject::invokeMethod(this, "addConnection", Qt::QueuedConnection);
            }

            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()));
        }

        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 occured 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 int primary key, Title varchar(50), Director varchar(20), Rating number(2,2))");
                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 int primary key, Firstname varchar(20), Lastname varchar(20), City varchar(20))");
                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')");
            } else {
                static int cCount = 0;
                QSqlDatabase db = QSqlDatabase::addDatabase(dialog.driverName(),
                                                            QString("Browser%1").arg(++cCount));
                db.setDatabaseName(dialog.databaseName());
                db.setHostName(dialog.hostName());
                db.setUserName(dialog.userName());
                db.setPassword(dialog.password());
                db.setPort(dialog.port());
                if (!db.open())
                    QMessageBox::warning(this, tr("Unable to open database"), tr("An error occured while "
                                                                                 "opening the connection: ") + db.lastError().text());
            }
            connectionWidget->refresh();
        }

        void Browser::showTable(const QString &t)
        {
            QSqlTableModel *model = new QSqlTableModel(table, connectionWidget->currentDatabase());
            model->setTable(t);
            model->select();
            if (model->lastError().type() != QSqlError::NoError)
                emit statusMessage(model->lastError().text());
            table->setModel(model);
        }