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 paint(self, c):
		self.leaf.paint(c)
		if self.lchild != None:
			self.lchild.paint(c)
		if self.rchild != None:
			self.rchild.paint(c)