Hello Mirko, Storing typestamps on statements is a partial case of reification. Unfortunately Virtuoso does not provide any special support for reification --- that would penalize other tasks.
Storing typestamps on subjects does not require reification and could be made via triggers, but these triggers do not have to be system, built-in triggers, they can be placed into the application. Instead of using triggers, the related functionality can be supported by tweaking system procedures, similarly to support for free text index data about graphs, but the development might take some time and will result in makinga branch in sources and keeping that branch in sync with the results of the mainstream development. Thus, try triggers first. In case of serious lack of performance something else could be tried, but not earlier. Best Regards, Ivan Mikhailov OpenLink Software http://virtuoso.openlinksw.com On Wed, 2009-11-18 at 16:09 +0100, Mirko wrote: > Hi, > I would like to (auto-)remove statements with a certain age from RDF graphs > in Virtuoso. In SQL I would create a "timestamp" column with DEFAULT > CURRENT_TIMESTAMP, ON UPDATE CURRENT_TIMESTAMP and add an event scheduler > that deletes all rows with a given age. > > I wonder what is the best way to do this using an RDF graph? Currently, I > insert extra statements with a timestamp for each RDF subject at application > level. (E.g. my:Subject my:hasObject my:Object . my:Subject my:lastUpdated > "timeStamp"). This is not very convenient and probably not very efficient. > > So, does Virtuoso provide a mechanism to attach and autoupdate timestamps to > RDF statements (and thus to remove old statements) at DB level? > > Thanks, Mirko > ------------------------------------------------------------------------------ > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day > trial. Simplify your report design, integration and deployment - and focus on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > _______________________________________________ > Virtuoso-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/virtuoso-users
