- From: Jan Algermissen <jalgermissen@topicmapping.com>
- Date: Sat, 25 Jun 2005 10:30:08 +0200
- To: Danny Ayers <danny.ayers@gmail.com>
- Cc: semantic-web@w3.org
Danny,
why don;tyou just put the current time in the query?
..where presentation-start <= "2005-06-24T15:05:00Z"
and prtesenation-end == null
(forgive me the SQL like query, not yet good enough at sparql).
(This brings up an issue I have with existing RDF databases: all of
them seem
not to be able to recognize literal datatypes for operator 'binding'.
For
example: the <= operator should work differently for dates than for
int and yet
for strings).
If you have a million+ dates, doing the <= operation with a full scan is
starting to be rediculous.
Thoughts?
Jan
On Jun 25, 2005, at 9:48 AM, Danny Ayers wrote:
>
> I've recently been looking at putting conference data into a
> triplestore with a SPARQL front-end . It will be desirable to ask
> questions like: "Who's presenting now?", "What did they post on their
> blogs in the last 24hrs?"
>
> I'm contemplating a statement generated on the fly:
>
> http://purl.org/stuff/datetime#Now rdf:value "2005-06-24T15:05:00Z"
>
> refreshing in the store immediately prior to each query.
>
> Following a couple of comments [1] when I mentioned this on my blog,
> I'd be interested in hearing if and where the logic screws up with
> this, and whether there aren't other (easy) approaches.
>
> Cheers,
> Danny.
>
> [1] http://dannyayers.com/archives/2005/06/24/dynamic-time-statements/
>
> --
>
> http://dannyayers.com
>
>
________________________________________________________________________
_______________
Jan Algermissen, Consultant & Programmer
http://jalgermissen.com
Tugboat Consulting, 'Applying Web technology to enterprise IT'
http://www.tugboat.de
Received on Saturday, 25 June 2005 08:30:30 UTC