比较DateTime结构以查找空闲插槽

我想搜索列表中所有用户的事件，并检索每个用户在上午7点到下午7点之间没有30分钟或更长时间的所有时间。

但是，如果某个方法被标记为“重复出现”，即比特重复出现设置为1，那么该事件将在其开始后的52周内重复出现（因此时间不可用）。 在存储过程中处理这些事件的检索。

到目前为止，我的代码如下。 我是否正在以正确的方式编写此程序？ 我不确定如何按照我的意愿继续使用函数返回。 有人能帮我这个吗？

List usernames = //List of usernames. DateTime start = //DateTime for start of period you would like to schedule meeting DateTime end = //DateTime for end of period //int mins = //duration of meeting (must be 30mins or greater) foreach (string username in usernames) { //retrieve events for this user var db = Database.Open("mPlan"); List startTimes; List<DateTime endTimes; // This stored procedure returns all events of a user in a given time period, // including recurring events. var record = db.Query("EXEC dbo.GetEvents @0, @1, @2", username, start, end); foreach(var record in result) { startTimes.Add(record.event_start); endTimes.Add(record.event_end); } // so now I have a list of all start times and end times of events // for one user and could save all this data in a list } 

表结构：

 DECLARE @Users TABLE ( UserID INT IDENTITY(1,1), Username VARCHAR(32) ); DECLARE @Groups TABLE ( GroupID INT IDENTITY(1,1), GroupName VARCHAR(32) ); DECLARE @Membership TABLE ( UserID INT, GroupID INT ); DECLARE @event TABLE ( event_id INT IDENTITY(1,1), event_start DATETIME, event_end DATETIME, group_id INT, recurring BIT ); 

我想要的function示例：

用户将数据库中的多个用户添加到列表中。 用户选择他希望与所有这些用户会面的时间段。 我的算法计算所有用户都可以免费使用的所有时间段（即适合在所有用户之间进行会议且超过30分钟的时间）。

附加信息 ：

示例案例：

• 用户A尝试与用户B组织会议。所有时段都是免费的。 我希望算法返回开始时间和结束时间的所有可能组合的DateTime start和DateTime结束，其中> 30mins和== duration（参数）。

• 典型案例：用户A计划在下午6点至晚上7点之间的所有时间进行活动。 他试图与用户B组织一次会议，持续时间为1小时。 用户B没有组织任何活动 – 返回DateTime 6PM和DateTime 7pm以指示会议的开始和结束时间。

• 重复案例：用户A在周一下午5点至下午6点举行重复活动。 他试图在六个星期的星期一组织一次2小时的会议。 DateTime start和DateTime的所有组合结束，返回2小时的差异。 下午5点至晚上7点的时间不会返回，因为此事件是重复发生的，每周发生一次，为期52周。

以下是存储过程，它检索设置时间段（开始，结束）的所有用户事件：

 ALTER PROCEDURE dbo.GetEvents @UserName VARCHAR(50), @StartDate DATETIME, @EndDate DATETIME AS BEGIN -- DEFINE A CTE TO GET ALL GROUPS ASSOCIATED WITH THE CURRENT USER ;WITH Groups AS ( SELECT GroupID FROM Membership m INNER JOIN Users u ON m.UserID = u.UserID WHERE Username = @UserName GROUP BY GroupID ), -- DEFINE A CTE TO GET ALL EVENTS FOR THE GROUPS DEFINED ABOVE AllEvents AS ( SELECT e.* FROM event e INNER JOIN Groups m ON m.GroupID = e.group_id UNION ALL SELECT e.event_id, e.title, e.description, DATEADD(WEEK, w.weeks, e.event_start), DATEADD(WEEK, w.weeks, e.event_end), e.group_id, e.recurring FROM event e INNER JOIN Groups m ON m.GroupID = e.group_id CROSS JOIN ( SELECT ROW_NUMBER() OVER (ORDER BY Object_ID) AS weeks FROM SYS.OBJECTS ) AS w WHERE e.recurring = 1 ) -- GET ALL EVENTS WHERE THE EVENTS FALL IN THE PERIOD DEFINED SELECT * FROM AllEvents WHERE Event_Start >= @StartDate AND Event_End <= @EndDate END 

Answer 1

想象一下表：

 USE tempdb; GO CREATE TABLE dbo.Users ( UserID INT IDENTITY(1,1), Username VARCHAR(32) ); CREATE TABLE dbo.Groups ( GroupID INT IDENTITY(1,1), GroupName VARCHAR(32) ); CREATE TABLE dbo.Membership ( UserID INT, GroupID INT ); CREATE TABLE dbo.[event] ( event_id INT IDENTITY(1,1), event_start DATETIME, event_end DATETIME, group_id INT, recurring BIT ); 

并且想象一些样本数据并不那么难以提供：

 INSERT dbo.Users(Username) SELECT 'User A' UNION ALL SELECT 'User B'; INSERT dbo.Groups(GroupName) SELECT 'Group 1' UNION ALL SELECT 'Group 2'; INSERT dbo.Membership(UserID, GroupID) SELECT 1,1 UNION ALL SELECT 2,2; INSERT dbo.[event](event_start, event_end, group_id, recurring) -- user A, almost all day meeting on a specific date SELECT '20120313 07:00', '20120313 18:00', 1, 0 -- user A, recurring meeting every Monday UNION ALL SELECT '20120312 17:00', '20120312 18:00', 1, 1 -- user A, recurring meeting every Tuesday (future) UNION ALL SELECT '20120327 14:00', '20120327 15:00', 1, 1; GO 

现在我们可以构建这个存储过程：

 CREATE PROCEDURE dbo.GetPossibleMeetingTimes @AskingUserID INT, @TargetUserID INT, @Duration INT, -- in minutes! @StartDate SMALLDATETIME, -- assumes date, no time! @EndDate SMALLDATETIME -- again - date, no time! AS BEGIN SET NOCOUNT ON; ;WITH dRange(d) AS ( -- get the actual dates in the requested range -- limited to number of rows in sys.objects SELECT TOP (DATEDIFF(DAY, @StartDate, @EndDate)+1) DATEADD(DAY, n-1, @StartDate) FROM (SELECT n = ROW_NUMBER() OVER (ORDER BY [object_id]) FROM sys.objects) AS x ), possible(ds, de) AS ( -- get all the timeslots of @Duration minutes -- between 7:00 AM and 7:00 PM for each day in -- the range - these are all *potential* slots SELECT DATEADD(MINUTE, 30*rn, DATEADD(HOUR, 7, dRange.d)), DATEADD(MINUTE, 30*rn + @Duration, DATEADD(HOUR, 7, dRange.d)) FROM (SELECT TOP (720/30) rn = ROW_NUMBER() OVER (ORDER BY [object_id])-1 FROM sys.objects) AS x CROSS JOIN dRange ) SELECT p.ds, p.de FROM possible AS p WHERE p.de <= DATEADD(HOUR, 19, DATEADD(DAY, DATEDIFF(DAY, 0, p.de), 0)) AND NOT EXISTS ( SELECT 1 FROM ( -- filter down to users with events on the days in the range SELECT group_id, event_start, event_end FROM dbo.[event] WHERE event_start >= @StartDate AND event_start < DATEADD(DAY, 1, @EndDate) UNION ALL -- also include users with recurring events on same weekday(s) -- normalized to the matching day in the range SELECT group_id, event_start = DATEADD(DAY, DATEDIFF(DAY, event_start, p.ds), event_start), event_end = DATEADD(DAY, DATEDIFF(DAY, event_end, p.ds), event_end) FROM dbo.[event] WHERE recurring = 1 AND event_start <= DATEADD(DAY, 1, @EndDate) -- ignore future events AND event_start >= DATEADD(WEEK, -52, @EndDate) -- 52 weeks out AND DATEDIFF(DAY, event_start, p.ds) % 7 = 0 -- same weekday ) AS sub WHERE sub.group_id IN ( -- this checks that events are within previously scheduled times SELECT GroupID FROM dbo.Membership WHERE UserID IN (@AskingUserID, @TargetUserID) AND (p.de > sub.event_start AND p.ds < sub.event_end) ) ) ORDER BY p.ds, p.de; END GO 

示例调用：

 -- Case 1: User A tries to meet with User B on a day where -- both schedules are clear. EXEC dbo.GetPossibleMeetingTimes @AskingUserID = 1, @TargetUserID = 2, @Duration = 30, @StartDate = '20120314', -- no events for either user @EndDate = '20120314'; 

结果：

 -- Case 2: User A tries to meet with User B for an hour, on -- a day where user A has meetings from 7 AM to 6 PM. EXEC dbo.GetPossibleMeetingTimes @AskingUserID = 1, @TargetUserID = 2, @Duration = 60, @StartDate = '20120313', -- user A has an almost all-day event @EndDate = '20120313'; 

结果：

 -- Case 3: User A tries to meet with User B for two hours, on -- a weekday where User A has a recurring meeting from 5-6 PM EXEC dbo.GetPossibleMeetingTimes @AskingUserID = 1, @TargetUserID = 2, @Duration = 120, @StartDate = '20120319', -- user A has a recurring meeting @EndDate = '20120319'; 

结果：

现在请注意，我处理了您未考虑或未提及的几个因素（例如将来开始的重复事件）。 另一方面，我也没有处理其他一些因素（例如，夏令时，如果它可能会影响到这一点），并且没有测试所有可能的情况（例如，已经存在的同一天的多个事件）。

我测试过，如果你通过一个范围（例如2012-03-12 - > 2012-03-14），你基本上只会得到上述结果的联合，大致相同的时间段可用（这些时间根据持续时间而有所不同）当然）。 重要的是，停电时段很荣幸。 我没有测试将来开始重复事件的情况的逻辑，并且提供的日期范围包括事件的第一个实例之前和之后的工作日。

如果任何情况对您不起作用，那么这就是为什么使用样本数据向您展示所有案例非常重要，而不是单词问题 ，并解释给定数据的查询所需结果。

编辑 - 要处理超过2个用户，您只需要进行一些更改。 如果添加拆分function，如下所示：

 CREATE FUNCTION dbo.SplitInts( @List VARCHAR(MAX) ) RETURNS TABLE AS RETURN ( SELECT Item = CONVERT(INT, Item) FROM ( SELECT Item = xivalue('(./text())[1]', 'INT') FROM ( SELECT [XML] = CONVERT(XML, '' + REPLACE(@List, ',', '') + '').query('.')) AS a CROSS APPLY [XML].nodes('i') AS x(i)) AS y WHERE Item IS NOT NULL ); 

现在对存储过程进行了非常小的更改（我遗漏了未更改的位）：

 ALTER PROCEDURE dbo.GetPossibleMeetingTimes @UserIDList VARCHAR(MAX), -- removed other two parameters @Duration INT, @StartDate SMALLDATETIME, @EndDate SMALLDATETIME AS ... WHERE sub.group_id IN -- changed the code within this subquery ( SELECT GroupID FROM dbo.Membership AS m INNER JOIN dbo.SplitInts(@UserIDList) AS i ON m.UserID = i.Item WHERE (p.de > sub.event_start AND p.ds < sub.event_end) ) ... 

那么你的电话会稍微改变一下：

 EXEC dbo.GetPossibleMeetingTimes @UserIDList = '1,2,3,4,5', @Duration = 30, @StartDate = '20120314', @EndDate = '20120314'; 

只需确保请求者包含在以逗号分隔的列表中。

PS这个附录未经测试。