@Override
    public UserImpl getUser(String userName, String password) {
        // open connection
        conn = CoreDao.open();
        if(conn == null) {
            System.out.println("getUser: Connection = null");
        }
        // prepare the statement
        try {
            selectUser = conn.prepareStatement("SELECT userId, keyId, users.pilotId, " +
                    "pilotName, vCode, password, email " +
                    "FROM users, pilots WHERE users.pilotId = " +
                    "pilots.pilotId AND users.userName = ?;");

            // get a result set
            selectUser.setString(1, userName);
            ResultSet resultSet = selectUser.executeQuery();

            // check if resultSet is empty
            if (resultSet.first()) {
                System.out.println("first check!"); // test
                return null;
            }
            // check if password cell is empty
            if (resultSet.getString(password) == null) {
                System.out.println("password == null check");   // test
                return null;
            }
            // check if password is correct
            if (!resultSet.getString(password).equals(password)) {
                System.out.println("password doesn't exist check"); // test
                return null;
            } else {
                return new UserImpl(resultSet.getInt("userId"), resultSet.getInt("keyId"),
                    resultSet.getInt("pilotId"), resultSet.getString("userName"),
                    resultSet.getString("password"), resultSet.getString("email"),
                    resultSet.getString("pilotName"), resultSet.getString("vCode"), null);
                }
        } catch (SQLException e) {
            e.printStackTrace();
            System.err.println("Unable to execute database query");
        } finally {
            try {
                selectUser.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            CoreDao.close(conn);
        }
        return null;
    }