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 draw_paths(c, tree):
	if tree.lchild == None or tree.rchild == None:
		return
	tree.lchild.leaf.draw_path(c, tree.rchild.leaf)
	draw_paths(c, tree.lchild)
	draw_paths(c, tree.rchild)