def robotsrulesetOfDomain(self, domain):
		'''检查domain是否在数据库中,
			否 --> (False, None)
			是 --> (True, 数据库中存储的robots.txt内容)
		'''
		exist = False
		cur = self.conn.cursor()
		# 是否存在
		cur.execute("SELECT 1 FROM Domains WHERE domain=?", (domain,))
		if cur.fetchone() :
			exist = True
		# 存在的话,结果是什么
		cur.execute("SELECT rules FROM Domains,Rulesets "
			"WHERE domain=? AND Domains.did=Rulesets.did"
			,(domain,) )
		ruleset = cur.fetchone()
		return (exist, ruleset)
def __init__(self, filename, errors):
        """
        :param filename: The name of the transaction file being replayed
        :param errors: a list of error classes or a string with an error description
        """

        # store args in case someone wants to read them from a caught exception
        self.filename = filename
        if isinstance(errors, (list, tuple)):
            self.errors = errors
        else:
            self.errors = [errors]

        if filename:
            msg = _('The following problems occurred while replaying the transaction from file "{filename}":').format(filename=filename)
        else:
            msg = _('The following problems occurred while running a transaction:')

        for error in self.errors:
            msg += "\n  " + str(error)

        super(TransactionReplayError, self).__init__(msg)