public List<DVD> findByLanguage(String param_language) {
		List<DVD> dvds = new ArrayList<DVD>();
		String query = "SELECT * FROM dvd WHERE language=?";
		em = dbUtil.getEntityManager();
		Query q = em.createNativeQuery(query, DVD.class);
		q.setParameter(1, param_language);
		dvds = q.getResultList();
		return dvds;
	}