Example of RSP-QL query

This query continuously look for bars where people are falling in love like Paolo and Francesca in Dante's Divine Comedy because of a book by Gallehault.

see most recent version at GitHub: https://github.com/streamreasoning/RSP-QL

The query checks :

• over the default graph containing the points of interest (POIs) of http://somesocialnetwork.org/ that the POI is a bar.
• over the a 4 hour long window on the stream from http://someinvasivesensornetwork.org, that pairs of people entered in the poi in different moments (if they enter together they get discarted).
• over the same stream, with a time window of 30 minutes in the past, that pairs of those people have been staying close by for at least 30 minutes. Note: that this may require some resoning being the property isCloseBy symmetric.
• over the same stream but with a short time window of 10 minutes, that the same pairs exit together.

As output, for each bar, it streams out an RDF graph with the list of pairs and the total number of pairs that felt in love.

Note that this example query covers features of C-SPARQL, CQELS, and SPARQL-Stream as well as new features missing in all RSP languages:

• From C-SPARQL it takes the REGISTER clause, the FROM STREAM clause as dataset clause, the AT clause to access the timestamp (in C-SPARQL, AT is implemented with the timestamp() function) and the aggregates (which are computed in parallel without shrinking the result set, but extending it).
• From CQELS it takes the idea of the STREAM keyword in the WHERE clause, herein defined as WINDOW.
• From SPARQL-Stream it takes the ISTREAM clasue, that ask the RSP engine to use the R2S operator, and the notion of windows in the past.

Differently from a previous version of this query, it no longer covers features of EP-SPARQL such as SEQ or the getDuration() function. This reflects the decision to layer the complex event processing language on a continuous querying one.

The new features are:

• the usage of an IRI to identify the query (and its stream of results)
• the optional UNDER ENTAILMENT REGIME clause
• the FROM NAMED WINDOW <<window IRI>> ON <<stream iri>> <<window>> clause in the dataset declaration
• the WINDOW keyword in the WHERE clause

PREFIX e: <http://somevocabulary.org/>
PREFIX s: <http://someinvasivesensornetwork.org/streams#>
PREFIX g: <http://somesocialnetwork.org/graphs#>
PREFIX : <http://acrasycompany.org/rsp>
REGISTER STREAM :GallehaultWasTheBar
UNDER ENTAILMENT REGIME <http://www.w3.org/ns/entailment/RIF>
AS
CONSTRUCT ISTREAM {
?poi rdf:type :Gallehault ;
:count ?howmanycouples ;
:for (?somebody ?someoneelse)
}
FROM NAMED WINDOW :veryLongWindow ON s:1 [RANGE PT4H STEP PT1H]
FROM NAMED WINDOW :longWindow ON s:1 [FROM NOW-PT35M TO NOW-PT5M STEP PT5M]
FROM NAMED WINDOW :shortWindow ON s:1 [RANGE PT10M STEP PT5M]
FROM NAMED GRAPH g:SocialGraph
FROM GRAPH g:POIs
WHERE {
 ?poi rdf:type e:bar .
 WINDOW :veryLongWindow {
  {?somebody e:enters ?poi} BEGIN AT ?t3
  {?someoneelse e:enters ?poi} BEGIN AT ?t4
  FILTER(?t3>?t4)
 }
 WINDOW :longWindow {
  {
   ?somebody e:isCloseTo ?someoneelse
   MINUS { ?somebody e:isCloseTo ?yetanotherone . FILTER (?yetanotherone != ?someoneelse) }
  } WITH DURATION ?duration
  FILTER (?duration>="PT30M"^^xsd:duration)
 }
 WINDOW :shortWindow {
  { ?somebody e:exits ?bar} BEGIN AT ?t1
  { ?someoneelse e:exits ?bar } BEGIN AT ?t2
  FILTER (abs(?t2-?t1)<"PT1M"^^xsd:duration )
 }
 GRAPH g:SocialGraph {
  FILTER NOT EXIST { ?somebody e:knows ?someoneelse }
 }
 FILTER (?somebody != ?someoneelse)
}
AGGREGATE {
GROUP BY ?poi
COUNT(?somebody) AS ?howmanycouples
}