def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def __get_linearForce_title_keys(lf):
    if 'force_r' in lf:
        return ['Force r', 'Force z'], ['force_r', 'force_z']
    return ['Force x', 'Force y'], ['force_x', 'force_y']