Re: Impossible Database Design?

Nikolai Onken wrote:
> > Anyone who gives detailed or emphatic opinions on the merits of the
> > design above is a crank.
>
> Hmm, why? Didn't I already state the set of requirements?
>
> 1. Repeating events without defined ending
> 2. Querying whether events overlap
> 3. Support of repeating patterns

Well, I'm not sure about what you've asked for. From the thread's subject, one would guess that you really don't want a database. After all, do you envision a table with an infinite number of rows for your on-going Thursday Night Poker Party? I doubt it.

I think, instead, you want a function/table function/procedure/operator that emits a stream of events which are scheduled to occur during some interval. In relational terms, I'd guess you seek a read-only operator giving a relation-valued result. The inputs? Two instants. The store of data used to generate the relation? I suspect you need something that represents time in a manner analgous to representations of lines, rays, and line segments -- along with something that represents a period.

Seems rather straightforward...

>
> An calendar entry could be a lesson, holiday, a graduation party, a
> semester, a birthday, a always repeating memorial,...
>
> Weird..
>
> I think that this design would support some sort of infinitely
> repeating events (limited on a time window though), would support
> queries over events in the future and would allow a pretty freely
> definable pattern syntax (depending how the software handles it)
> Regards,
>
> Nikolai
Received on Wed May 17 2006 - 17:32:08 CEST