Question

I have a message model and I want it to have several receivers, possibly a lot of them. I would also like to be able to tell for each receiver if the message was viewed or not (read/unread). Also I would like a receiver to be able to delete the message.

两种可能的解决方案如下,因为每个我都有一个宣传模式,即用户模式。

第一部分(利用以下介绍的想法:
我有一个“信息接收器”类别,有一个包含接收电文的用户名单,并将母子放在电文上。一、导言信息接收器 WHERE接收器 = :1, 用户), 并且是db.get(电文中的关键内容是: /code>。
The problem I have which this is that I m not sure how to store the state of the message: whether it is read or not and a subsequent issue whether the user has new messages. An additional issue would be the overhead of deleting a message (would have to remove user from receivers list property)


For the second: I have a MessageReceiver for each receiver it has links to message and to user and also stores the state (read/unread).



Which of this two approached do you consider that it has a better performance? And in the case of the first do you have any suggestion on handling the status of the message.

Answer 1

I ve implement first option in production. Drawback is that ListProperty is limited to 2500 entries if you use custom index. Shameless plug: See my blog bost http://bravenewmethod.wordpress.com/2011/03/23/developing-on-google-app-engine-for-production/

阅读状态储存。我之所以这样做,是因为执行了一个实体,在几个月后储存了无法读到的信息,然后才算读了旧的信息。更简单的做法是按日期顺序询问电文,在实体中储存最后已知的信息时段,并假定所有年长者都读到。我不建议把历史长期保留在拥有大量清单财产的实体中,因为阅读和储存这类实体确实会缓慢。

删除电文是昂贵的,根本不是这样。

Answer 2

如果你需要存储每个信息,那么你的最佳选择是每个接收实体写一个读写(以及旗帜、 etc等任何其他东西),而不是使用指数关系模式。

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