Question

I m 提出申请

stores an e-mail address (to a user) in a table.
stores the number of days the user would like to stay in the table.
takes the user off the table when the number of days is up.

我并不真正知道如何处理这一问题,因此我的问题是:

Each second, do I have the application check through every table entry for the time that s currently stored in, let s say, the time_left column?
Wouldn t (1) be inefficient if I m expecting a significant number (10,000+) users?
If not (2), what s the best algorithm to implement for such a task?
What s the name of what I m trying to do here? I d like to do some more research on it before and while I m writing the script, so I need a good search query to start with.

我计划用Perl语撰写这一文字,尽管我愿意接受有关语言选择、框架等的建议。我实际上对网络发展(后端和前端)来说是新的,因此,如果你能够向我提供准确的咨询意见,我会不胜感激。

谢谢!

* 在张贴之后,。询问一个有效问题:

Why would you store users if they won t get requested?

用户刚刚在数据库中开庭。

从用户输入数据库后每5分钟使用用户电子邮件地址说一米(如果用户条目在2:00PM-10月18日出生,用户可在2:05、2:10等查询)。

如果用户在10天内决定希望从数据库中删除,这意味着其输入通常(每5分钟从2:00PM-October 18)到2:00PM-October 28。

So to clarify, based on this situation:

www.un.org/Depts/DGACM/index_spanish.htm 该系统必须不断将目前的时间与用户的到期日期进行比较?

Answer 1

You could write a separate program/script which makes the delete query on a set interval. If you are on a Linux machine you can create a cron job to do it. Doing it every second may become very resource intensive for slower machines and larger tables, but I don t believe that will become an issue for a simple delete query.

Answer 2

您不应储存时间——电子变数,否则就应当储存。这样,只要用户要求数据库,你就可以检查其是否有效。

否则,你会想做什么。

这种做法使你能够做任何工作,或者将给你带来额外负担。

Answer 3

Hey Mr_spock I like the above answer from Topener. Instead of storing a number of days the user would like to be valid, store the day the user would like to be be removed.

Adding a field like validToDate, which would be a DATETIME field type, you can do a query like

delete from tablename 地点validToDate <= NOW()

地点

the italicized text is a SQL query
tablename is the name of the table in question
NOW() is a valid sql function that returns the current DATETIME
validToDate is a field of type DATETIME

有了效率高的服务器的承诺,我认为这相当好。

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