def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def __init__(self, test, nh, pmtu, table_id=0):
        self._test = test
        self.nh = nh
        self.pmtu = pmtu
        self.table_id = table_id