我会给出两个答案,首先考虑RFC 5545的重复规则格式,并在应用层进行验证。
由于这可能不是您正在寻找的答案,因此我还建议查看本周的任何一点作为从周开始的偏移量。
然后,您可以建立一个转换列表,这些转换列表定义了交易所打开或关闭的周内的偏移量。所需的唯一约束是验证偏移量是否有效(少于7天),并且开放到闭合的转换只是紧跟在后面的转换(反之亦然)。
我没有一个Oracle对话框打开在打转转,但这里是在T-SQL的例子:
create table #sched (exchangeID int, weekOffset int, isOpen bit)
insert into #sched
values (1, 400, 1),
(1, 800, 0),
(1, 1200, 1),
(1, 1700, 0);
-- constraints are that isOpen cannot be repeated. 1->0->1 is valid, 1->1->0 is not
declare @coffset int,
@weekStart datetime;
set @weekstart = dateadd(week, datediff(week, 0, getdate()), 0);
set @coffset = datediff(minute, @weekStart, getdate());
with trans (uniqid, exch, offset, isopen)
as
(
select ROW_NUMBER() OVER (ORDER BY weekoffset), *
from (
SELECT exchangeID, weekoffset - 7*24*60 as weekoffset, isopen from #sched
UNION
select exchangeID, weekoffset, isopen from #sched
UNION
select exchangeID, weekoffset + 7*24*60, isopen from #sched
) as inr
)
select *,
CASE pt.IsOpen
WHEN 1 THEN 'Exchange is now open and will close at ' + CAST(DATEADD(minute, nt.offset, @weekstart) as varchar(20))
ELSE 'Exchange is now closed and will open at ' + CAST(DATEADD(minute, nt.offset, @weekstart) as varchar(20)) END
from (
SELECT MIN(uniqid) as nextTransition
FROM trans
WHERE offset > @coffset
) as n
cross join (
SELECT MAX(uniqid) as prevTransition
FROM trans
WHERE offset <= @coffset
) as p
inner join trans as nt on nt.uniqid = nextTransition
inner join trans as pt on pt.uniqid = prevTransition
drop table #sched
Results上sqlfiddle:
| NEXTTRANSITION | PREVTRANSITION | UNIQID | EXCH | OFFSET | ISOPEN | COLUMN_10 |
|----------------|----------------|--------|------|--------|--------|-------------------------------------------------------------|
| 9 | 8 | 9 | 1 | 10480 | 1 | Exchange is now closed and will open at Feb 24 2014 6:40AM |