/**
	 * Get all users added to the database as persistent user objects
	 * 
	 * @return	ArrayList with persistent user objects or null if empty
	 */
	public ArrayList<PersUser> getAllUsers() {
		String sql = "SELECT id FROM " + getTable();
		Vector<Integer> v = new Vector<Integer>();
		ArrayList<PersUser> pus = new ArrayList<PersUser>();
		
		try {
			ResultSet rs = select(sql);
			
			while(rs.next()) v.add(rs.getInt("id"));
			
			for(Integer id: v) pus.add(getUser(id));
			
			if(v.size() == 0) return null;
			else return pus;
		} catch (SQLException e) {
			e.printStackTrace();
			
			return null;
		}