Re: Expressiveness of the RSP-QL query language

Hello Robin, all!

Am 15.12.2014 um 08:46 schrieb Robin Keskisärkkä:
> Thanks for the response Emanuele. Just to clarify, since only one triple
> is used in each graph pattern with a BEGIN AT. I assume we regard the
> individual triples in each graph to be associated with the specific
> timestamps of the originally streamed graph, so that a graph can be
> referenced using it's associated timestamp, e.g.:
> { ?somebody e:enters ?poi; g:drunk "false"} BEGIN AT ?t 
> expresses that "somebody" entered "poi" and was at the same point in
> time not "drunk" within the same window?

'Not "drunk" within the same window' is true but 'Not "drunk" at the
same point in time' is not:

1.: It is reasonable to require that triples are associated with graphs
and as such are timestamped (like graphs are).

2.: However, there can be cases a triple e.g. { ?somebody e:enters ?poi
} could result from several graphs e.g. in a time window. Then we need a
way to uniquely select/associate one graph for such a triple. (An
example would be to use the triple with the *newest* graph for the
BEGIN/END operators.)

There is no conclusion here. However, I think we need a better semantics
or re-think those graph-oriented operators.

Roland.

Received on Monday, 15 December 2014 10:17:54 UTC