Question

我正在寻找用于存储重复事件的数据结构模式，但我提出的所有内容都会导致大量特殊情况处理或用户输入和数据检索过于复杂。（我得到了明显的感觉，我还没有完全理解问题领域。）

如何存储Outlook风格的定期事件？

每天上午8点
每个月的第一个星期二
每年12月1日三年
每两个小时一周
...

Answer 1

支持标准 iCalendar 事件类型

IETF在创建 Internet日历和计划核心对象规范时更加深思熟虑，更好地称为 iCalendar 。

规范包括事件重现。

作为额外的奖励，您的数据库可以与其他iCalendar兼容数据源（如Google和Apple日历）共享数据。

http://tools.ietf.org/html/rfc5545

Answer 2

有各种论文描述了这个用例的数据结构和算法。此外，您还可以查看crontab和Quartz（Java）或Quartz.NET（.NET）的开源实现的代码或说明。

这是一篇这样的论文

http://portal.acm.org/citation.cfm?id=359763.359801&coll=ACM&dl=ACM&CFID=63647367&CFTOKEN=55814330

例如，cron存储这样的信息（*表示每个，因此每个月*表示每个月）


.---------------- minute (0 - 59) 
|  .------------- hour (0 - 23)
|  |  .---------- day of month (1 - 31)
|  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ... 
|  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7)  OR sun,mon,tue,wed,thu,fri,sat 
|  |  |  |  |
*  *  *  *  * 

There are several special entries, most of which are just shortcuts, 
that can be used instead of specifying the full cron entry:

Entry      Description                 Equivalent To
@reboot    Run once, at startup.       None
@yearly    Run once a year             0 0 1 1 *
@annually  (same as @yearly)           0 0 1 1 *
@monthly   Run once a month            0 0 1 * *
@weekly    Run once a week             0 0 * * 0
@daily     Run once a day              0 0 * * *
@midnight  (same as @daily)            0 0 * * *
@hourly    Run once an hour            0 * * * *

Answer 3

Event:

StartDate
EndDate (calculated on change of NumberOfOccurances)
NumberOfOccurances (calculated on change of EndDate )
Frequency e.g. 1/2hrs, 1/month, 1/day, ....
CorrectionFunction e.g. first Tuesday, last Sunday, ...

bool OccuresOn(day)
Date NextOccurance(date)

Answer 4

这是我的看法 - 请告诉我，如果我遗漏了任何东西：

根据Outlook Recurrence选项，您有一个包含常规必填字段的表：

FieldName       DataType      Sample Data
ID              int           primary key
EventID         int           foreign key (to EventID from Event Table)
StartTime       DateTime      8:00 AM
EndTime         DateTime      8:30 AM
Duration        int           30 (minutes)
StartDate       DateTime      01/25/2014
EndBy           DateTime      01/25/2024
NoEndDate       bit           False
NumOccurrences  int           10
RecurrenceType  int           ****See below for instructions on how to use these last 6 fields  
Int1            int           
Int2            int
Int3            int
String1         nvarchar(50)
IntYears        int

这就是魔术发生的地方。这个逻辑只需要4个整数和一个字符串。

The month of year (1 = Jan, 12 = Dec), 
The day of the month (1 = the 1st, 31 = 31st), 
Day of the week (0 = Sunday, 1=Monday, 6= Saturday), 
Week of the month (1 = first, 4 = forth, 5 = last),
Yearly reocurrence ( 1=1,2=2)   
When multiple days can be selected I use a comma delimited string (1,3,5 = Monday, Wed, Friday)

我按照它们在outlook Appointment Recurrence调度程序中出现的顺序输入3个整数，这样可以节省额外的费用，逻辑，烦恼。 * 如果您对outlook appt计划程序开放，则会更容易理解：

The RecurrenceType field can be any of the 7 following choices

（每日，每月和每年有2个选项，每周有一个选项）：

10 = Daily (Every `Int1` day(s) )    
            Every     4  day(s)
11 = Daily (Every Weekday)  -- no variables needed 
            Every Weekday (MTWTF)
20 = Weekly (Recur every `Int1` week(s) on: `String1`
             Recur every     3  week(s) on  Monday, Wednesday, Friday   
(`String1` will be a list of days selected (0=Sunday, 1=Monday, 2=Tuesday... 7=Saturday) so for (Mon, Wed, Fri) String1 would hold "1,3,5". You would parse this on the code side to pull the actual days.)
30 = Monthly (Day `Int1` of every `int2' month(s) 
              Day    28  of every     2  month(s)
31 = Monthly (The `Int1`  `Int2` of every `Int3` month(s) 
              The forth Tuesday  of every     1  month(s)
40 = Yearly (Recur every `intYears` year(s) On `Int1` `Int2`) -- 
             Recur every         1  year(s) on   Jan   28th
41 = Yearly (Recur every `intYears` year(s) on the `Int1` `Int2` of `Int3`) -- 
             Recur every         1  year(s) on the forth Tuesday of January

拉动或保存重现的代码变得相当简单

if (RecurrenceType = 10 )
    Every `int1` days
if (RecurrenceType = 11)
    Every Weekday
if (RecurrenceType = 20)
    Every `int1 weeks on 
    parse `string1` and populate checkboxes for Mon, Tues, ...
if (RecurrenceType = 30)
    `int1 day of every `int2` month

etc...

我希望我能够彻底解释这一点。如果有什么不清楚或是否不起作用，请告诉我。我正在为当前的应用程序构建此功能。谢谢大家。

用于存储重复事件的数据结构？

4 个答案: