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 linear_search(lst,size,value):
    i = 0
    while i < size:
        if lst[i] == value:
            return i
        i = i + 1
    return -1