initdb.h Example File

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  #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