def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def setTail(self, pt):
        self.pt = pt
        self.Tail.Eq(pt)
        self.Head.setPoint(self.pt.x + self.x, self.pt.y + self.y)