path: root/src/sql/doc/snippets/sqldatabase/sqldatabase_snippet.cpp

// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

//! [16]
    QSqlQueryModel *model = new QSqlQueryModel;
    model->setQuery("SELECT name, salary FROM employee");
    model->setHeaderData(0, Qt::Horizontal, tr("Name"));
    model->setHeaderData(1, Qt::Horizontal, tr("Salary"));
//! [17]
    QTableView *view = new QTableView;
//! [17] //! [18]
    view->setModel(model);
//! [18] //! [19]
    view->show();
//! [16] //! [19] //! [20]
    view->setEditTriggers(QAbstractItemView::NoEditTriggers);
//! [20]
    }

//! [21]
    QSqlQueryModel model;
    model.setQuery("SELECT name, salary FROM employee");
    int salary = model.record(4).value("salary").toInt();
//! [21]
    Q_UNUSED(salary);

    {
//! [22]
    int salary = model.data(model.index(4, 1)).toInt();
//! [22]
    Q_UNUSED(salary);
    }

    for (int row = 0; row < model.rowCount(); ++row) {
        for (int col = 0; col < model.columnCount(); ++col) {
            qDebug() << model.data(model.index(row, col));
        }
    }
}

class MyModel : public QSqlQueryModel
{
public:
    QVariant data(const QModelIndex &item, int role) const override;
    void fetchModel();

    int m_specialColumnNo;
};

//! [23]
QVariant MyModel::data(const QModelIndex &item, int role) const
{
    if (item.column() == m_specialColumnNo) {
        // handle column separately
    }
    return QSqlQueryModel::data(item, role);
}
//! [23]

void QSqlTableModel_snippets()
{
//! [24]
    QSqlTableModel *model = new QSqlTableModel;
    model->setTable("employee");
    model->setEditStrategy(QSqlTableModel::OnManualSubmit);
    model->select();
    model->setHeaderData(0, Qt::Horizontal, tr("Name"));
    model->setHeaderData(1, Qt::Horizontal, tr("Salary"));

    QTableView *view = new QTableView;
    view->setModel(model);
    view->hideColumn(0); // don't show the ID
    view->show();
//! [24]

    {
//! [25]
    QSqlTableModel model;
    model.setTable("employee");
    model.select();
    int salary = model.record(4).value("salary").toInt();
//! [25]
    }
}

void sql_intro_snippets()
{
    {
//! [26]
    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
    db.setHostName("bigblue");
    db.setDatabaseName("flightdb");
    db.setUserName("acarlson");
    db.setPassword("1uTbSbAs");
    bool ok = db.open();
//! [26]
    Q_UNUSED(ok);
    }

    {
//! [27]
    QSqlDatabase firstDB = QSqlDatabase::addDatabase("QMYSQL", "first");
    QSqlDatabase secondDB = QSqlDatabase::addDatabase("QMYSQL", "second");
//! [27]
    }

    {
//! [28]
    QSqlDatabase defaultDB = QSqlDatabase::database();
//! [28] //! [29]
    QSqlDatabase firstDB = QSqlDatabase::database("first");
//! [29] //! [30]
    QSqlDatabase secondDB = QSqlDatabase::database("second");
//! [30]
    }

    {
    // SELECT1
//! [31]
    QSqlQuery query;
    query.exec("SELECT name, salary FROM employee WHERE salary > 50000");
//! [31]

//! [32]
    while (query.next()) {
        QString name = query.value(0).toString();
        int salary = query.value(1).toInt();
        qDebug() << name << salary;
    }
//! [32]
    }

    {
    // FEATURE
//! [33]
    QSqlQuery query;
    int numRows;
    query.exec("SELECT name, salary FROM employee WHERE salary > 50000");

    QSqlDatabase defaultDB = QSqlDatabase::database();
    if (defaultDB.driver()->hasFeature(QSqlDriver::QuerySize)) {
        numRows = query.size();
    } else {
        // this can be very slow
        query.last();
        numRows = query.at() + 1;
    }
//! [33]
    }

    {
    // INSERT1
//! [34]
    QSqlQuery query;
    query.exec("INSERT INTO employee (id, name, salary) "
               "VALUES (1001, 'Thad Beaumont', 65000)");
//! [34]
    }

    {
    // NAMED BINDING
//! [35]
    QSqlQuery query;
    query.prepare("INSERT INTO employee (id, name, salary) "
                  "VALUES (:id, :name, :salary)");
    query.bindValue(":id", 1001);
    query.bindValue(":name", "Thad Beaumont");
    query.bindValue(":salary", 65000);
    query.exec();
//! [35]
    }

    {
    // POSITIONAL BINDING
//! [36]
    QSqlQuery query;
    query.prepare("INSERT INTO employee (id, name, salary) "
                  "VALUES (?, ?, ?)");
    query.addBindValue(1001);
    query.addBindValue("Thad Beaumont");
    query.addBindValue(65000);
    query.exec();
//! [36]
    }

    {
    // UPDATE1
//! [37]
    QSqlQuery query;
    query.exec("UPDATE employee SET salary = 70000 WHERE id = 1003");
//! [37]
    }

    {
    // DELETE1
//! [38]
    QSqlQuery query;
    query.exec("DELETE FROM employee WHERE id = 1007");
//! [38]
    }

    {
    // TRANSACTION
//! [39]
    QSqlDatabase::database().transaction();
    QSqlQuery query;
    query.exec("SELECT id FROM employee WHERE name = 'Torild Halvorsen'");
    if (query.next()) {
        int employeeId = query.value(0).toInt();
        query.exec("INSERT INTO project (id, name, ownerid) "
                   "VALUES (201, 'Manhattan Project', "
                   + QString::number(employeeId) + ')');
    }
    QSqlDatabase::database().commit();
//! [39]
    }

    {
    // SQLQUERYMODEL1
//! [40]
    QSqlQueryModel model;
    model.setQuery("SELECT * FROM employee");

    for (int i = 0; i < model.rowCount(); ++i) {
        int id = model.record(i).value("id").toInt();
        QString name = model.record(i).value("name").toString();
        qDebug() << id << name;
    }
//! [40]
    }

    {
    // SQLTABLEMODEL1
//! [41]
    QSqlTableModel model;
    model.setTable("employee");
    model.setFilter("salary > 50000");
    model.setSort(2, Qt::DescendingOrder);
    model.select();

    for (int i = 0; i < model.rowCount(); ++i) {
        QString name = model.record(i).value("name").toString();
        int salary = model.record(i).value("salary").toInt();
        qDebug() << name << salary;
    }
//! [41]
    }

    {
    // SQLTABLEMODEL2
    QSqlTableModel model;
    model.setTable("employee");

//! [42]
    for (int i = 0; i < model.rowCount(); ++i) {
        QSqlRecord record = model.record(i);
        double salary = record.value("salary").toInt();
        salary *= 1.1;
        record.setValue("salary", salary);
        model.setRecord(i, record);
    }
    model.submitAll();
//! [42]

    // SQLTABLEMODEL3
    int row = 1;
    int column = 2;
//! [43]
    model.setData(model.index(row, column), 75000);
    model.submitAll();
//! [43]

    // SQLTABLEMODEL4
//! [44]
    model.insertRows(row, 1);
    model.setData(model.index(row, 0), 1013);
    model.setData(model.index(row, 1), "Peter Gordon");
    model.setData(model.index(row, 2), 68500);
    model.submitAll();
//! [44]

//! [45]
    model.removeRows(row, 5);
//! [45] //! [46]
    model.submitAll();
//! [46]
    }
}

//! [47]
class XyzResult : public QSqlResult
{
public:
    XyzResult(const QSqlDriver *driver)
        : QSqlResult(driver) {}
    ~XyzResult() {}

protected:
    QVariant data(int /* index */) override { return QVariant(); }
    bool isNull(int /* index */) override { return false; }
    bool reset(const QString & /* query */) override { return false; }
    bool fetch(int /* index */) override { return false; }
    bool fetchFirst() override { return false; }
    bool fetchLast() override { return false; }
    int size() override { return 0; }
    int numRowsAffected() override { return 0; }
    QSqlRecord record() const override { return QSqlRecord(); }
};
//! [47]

//! [48]
class XyzDriver : public QSqlDriver
{
public:
    XyzDriver() {}
    ~XyzDriver() {}

    bool hasFeature(DriverFeature /* feature */) const override { return false; }
    bool open(const QString & /* db */, const QString & /* user */,
              const QString & /* password */, const QString & /* host */,
              int /* port */, const QString & /* options */) override
        { return false; }
    void close() {}
    QSqlResult *createResult() const override { return new XyzResult(this); }
};
//! [48]

int main(int argc, char **argv)
{
    QCoreApplication app(argc, argv);

    QSqlDatabase_snippets();
    QSqlField_snippets();
    QSqlQuery_snippets();
    QSqlQueryModel_snippets();
    QSqlTableModel_snippets();

    XyzDriver driver;
    XyzResult result(&driver);
}