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

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 **
 ** Copyright (C) 2004-2008 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.
 **
 ** This file is part of the documentation of the Qt Toolkit.
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 ** contact qt-sales@nokia.com if any conditions of this licensing
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 ** http://trolltech.com/products/appdev/licensing.
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 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 ** 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);

     table->addAction(insertRowAction);
     table->addAction(deleteRowAction);

     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 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 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 occured while "
                                        "opening the connection: ") + err.text());
     }
 }

 void Browser::showTable(const QString &t)
 {
     QSqlTableModel *model = new QSqlTableModel(table, connectionWidget->currentDatabase());
     model->setEditStrategy(QSqlTableModel::OnRowChange);
     model->setTable(t);
     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(), SIGNAL(currentRowChanged(QModelIndex,QModelIndex)),
             this, SLOT(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(QVariant::typeToName(fld.type()))
                 : QString("%1 (%2)").arg(QVariant::typeToName(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;

     model->setEditStrategy(QSqlTableModel::OnManualSubmit);

     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());
     }

     model->submitAll();
     model->setEditStrategy(QSqlTableModel::OnRowChange);

     updateActions();
 }

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

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

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