Qt 5.11 | Qt SQL | Books | initdb.h Example File

Qt 5.11.3 Reference Documentation

# initdb.h Example File

books/initdb.h

      /****************************************************************************
      **
      ** Copyright (C) 2016 The Qt Company Ltd.
      ** Contact: https://www.qt.io/licensing/
      **
      ** This file is part of the demonstration applications of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** Commercial License Usage
      ** Licensees holding valid commercial Qt licenses may use this file in
      ** accordance with the commercial license agreement provided with the
      ** Software or, alternatively, in accordance with the terms contained in
      ** a written agreement between you and The Qt Company. For licensing terms
      ** and conditions see https://www.qt.io/terms-conditions. For further
      ** information use the contact form at https://www.qt.io/contact-us.
      **
      ** BSD License Usage
      ** Alternatively, 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 The Qt Company Ltd 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."
      **
      ** $QT_END_LICENSE$
      **
      ****************************************************************************/

      #ifndef INITDB_H
      #define INITDB_H

      #include <QtSql>

      void addBook(QSqlQuery &q, const QString &title, int year, const QVariant &authorId,
                   const QVariant &genreId, int rating)
      {
          q.addBindValue(title);
          q.addBindValue(year);
          q.addBindValue(authorId);
          q.addBindValue(genreId);
          q.addBindValue(rating);
          q.exec();
      }

      QVariant addGenre(QSqlQuery &q, const QString &name)
      {
          q.addBindValue(name);
          q.exec();
          return q.lastInsertId();
      }

      QVariant addAuthor(QSqlQuery &q, const QString &name, const QDate &birthdate)
      {
          q.addBindValue(name);
          q.addBindValue(birthdate);
          q.exec();
          return q.lastInsertId();
      }

      QSqlError initDb()
      {
          QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
          db.setDatabaseName(":memory:");

          if (!db.open())
              return db.lastError();

          QStringList tables = db.tables();
          if (tables.contains("books", Qt::CaseInsensitive)
              && tables.contains("authors", Qt::CaseInsensitive))
              return QSqlError();

          QSqlQuery q;
          if (!q.exec(QLatin1String("create table books(id integer primary key, title varchar, author integer, genre integer, year integer, rating integer)")))
              return q.lastError();
          if (!q.exec(QLatin1String("create table authors(id integer primary key, name varchar, birthdate date)")))
              return q.lastError();
          if (!q.exec(QLatin1String("create table genres(id integer primary key, name varchar)")))
              return q.lastError();

          if (!q.prepare(QLatin1String("insert into authors(name, birthdate) values(?, ?)")))
              return q.lastError();
          QVariant asimovId = addAuthor(q, QLatin1String("Isaac Asimov"), QDate(1920, 2, 1));
          QVariant greeneId = addAuthor(q, QLatin1String("Graham Greene"), QDate(1904, 10, 2));
          QVariant pratchettId = addAuthor(q, QLatin1String("Terry Pratchett"), QDate(1948, 4, 28));

          if (!q.prepare(QLatin1String("insert into genres(name) values(?)")))
              return q.lastError();
          QVariant sfiction = addGenre(q, QLatin1String("Science Fiction"));
          QVariant fiction = addGenre(q, QLatin1String("Fiction"));
          QVariant fantasy = addGenre(q, QLatin1String("Fantasy"));

          if (!q.prepare(QLatin1String("insert into books(title, year, author, genre, rating) values(?, ?, ?, ?, ?)")))
              return q.lastError();
          addBook(q, QLatin1String("Foundation"), 1951, asimovId, sfiction, 3);
          addBook(q, QLatin1String("Foundation and Empire"), 1952, asimovId, sfiction, 4);
          addBook(q, QLatin1String("Second Foundation"), 1953, asimovId, sfiction, 3);
          addBook(q, QLatin1String("Foundation's Edge"), 1982, asimovId, sfiction, 3);
          addBook(q, QLatin1String("Foundation and Earth"), 1986, asimovId, sfiction, 4);
          addBook(q, QLatin1String("Prelude to Foundation"), 1988, asimovId, sfiction, 3);
          addBook(q, QLatin1String("Forward the Foundation"), 1993, asimovId, sfiction, 3);
          addBook(q, QLatin1String("The Power and the Glory"), 1940, greeneId, fiction, 4);
          addBook(q, QLatin1String("The Third Man"), 1950, greeneId, fiction, 5);
          addBook(q, QLatin1String("Our Man in Havana"), 1958, greeneId, fiction, 4);
          addBook(q, QLatin1String("Guards! Guards!"), 1989, pratchettId, fantasy, 3);
          addBook(q, QLatin1String("Night Watch"), 2002, pratchettId, fantasy, 3);
          addBook(q, QLatin1String("Going Postal"), 2004, pratchettId, fantasy, 3);

          return QSqlError();
      }

      #endif