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initdb.h Example File
demos/books/initdb.h

 /****************************************************************************
 **
 ** Copyright (C) 2005-2008 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.
 **
 ** This file is part of the documentation of the Qt Toolkit.
 **
 ** Licensees holding a valid Qt License Agreement may use this file in
 ** accordance with the rights, responsibilities and obligations
 ** contained therein.  Please consult your licensing agreement or
 ** contact [email protected] if any conditions of this licensing
 ** agreement are not clear to you.
 **
 ** Further information about Qt licensing is available at:
 ** http://trolltech.com/products/appdev/licensing.
 **
 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 **
 ****************************************************************************/

 #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