def updateInfo(self, item, newlinks, oldlinks):
		'''爬虫爬完之后对数据库内容进行更新'''
		cur = self.conn.cursor()
		cur.execute("SELECT wid,did FROM Websites WHERE url=?", (item['url'],))
		wid, did = cur.fetchone()
		# website记录更新
		cur.execute("UPDATE Websites SET title=?,visited=1 WHERE wid=?", (item['title'], wid,))
		# 对应的domain记录中出度也需要更新
		cur.execute("UPDATE Domains SET outdegree=outdegree+? WHERE did=?", (len(item['links']), did,))

		# 对该网页中所有链接涉及的记录进行更新
		# 外部判断未出现过的链接
		for link,domain in newlinks:
			self.insertWebsite(link, domain)

		# 外部判断出现过的链接
		for link,domain in oldlinks:
			# 对对应的domain记录入度增加
			cur.execute("UPDATE Domains SET outdegree=outdegree+1 WHERE domain=?", (domain,))
		# 写入到文件
		self.conn.commit()
def db_sync(engine, abs_path, version=None, init_version=0, sanity_check=True):
    """Upgrade or downgrade a database.

    Function runs the upgrade() or downgrade() functions in change scripts.

    :param engine:       SQLAlchemy engine instance for a given database
    :param abs_path:     Absolute path to migrate repository.
    :param version:      Database will upgrade/downgrade until this version.
                         If None - database will update to the latest
                         available version.
    :param init_version: Initial database version
    :param sanity_check: Require schema sanity checking for all tables
    """

    if version is not None:
        try:
            version = int(version)
        except ValueError:
            raise exception.DbMigrationError(
                message=_("version should be an integer"))

    current_version = db_version(engine, abs_path, init_version)
    repository = _find_migrate_repo(abs_path)
    if sanity_check:
        _db_schema_sanity_check(engine)
    if version is None or version > current_version:
        return versioning_api.upgrade(engine, repository, version)
    else:
        return versioning_api.downgrade(engine, repository,
                                        version)