def insertRuleset(self, ruleset, domain):
		'''增加一个robots.txt规则集'''
		cur = self.conn.cursor()
		cur.execute("SELECT did FROM Domains WHERE domain=?", (domain,))
		did = cur.fetchone()[0]
		cur.execute("INSERT INTO Rulesets VALUES (NULL,?,?)",(did, ruleset))
		# 写入到文件
		self.conn.commit()
def __exit__(self, exc_type, exc_val, exc_tb):
        connection = connections[get_tenant_database_alias()]

        connection.set_tenant(self._previous_tenant.pop())