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 select_all(self, event=None):
        self.tag_add(SEL, "1.0", "end-1c")
        self.mark_set(INSERT, "1.0")
        self.see(INSERT)
        return "break"