Qt 4.3: initdb.h Example File (demos/books/initdb.h)

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

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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