Qt 4.0: initdb.h Example File (demos/books/initdb.h)

|  | Home · All Classes · Main Classes · Grouped Classes · Modules · Functions |

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

        #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