browser.cpp Example File

sqlbrowser/browser.cpp
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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(), 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(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();
}

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.