def insertDomain(self, domain, indegree=0, outdegree=0):
		'''增加一个域名'''
		cur = self.conn.cursor()
		cur.execute("INSERT INTO Domains VALUES (NULL,?,?,?)", (domain, indegree, outdegree))
		# 写入到文件中
		self.conn.commit()
def getUseageMessage(self):
        return ("- TECHORANGE -\n"
                "useage:\n"
                "index - download entry page of TECHORANGE \n"
                "tag - download not obtained tag page \n"
                "news [tag] - download not obtained news [of given tag] \n")