Details

    • Type: Bug
    • Status: Closed - Won't Fix
    • Resolution: Duplicate
    • Affects Version/s: BIGDATA_RELEASE_1_2_0
    • Fix Version/s: None
    • Component/s: Bigdata SAIL
    • Labels:
      None

      Description

      Some of the property path features
      http://www.w3.org/TR/sparql11-query/#pp-language
      are giving incorrect results. In some cases it seems like the property path operator is being silently ignored.

      Given this test data:

      PREFIX : <http://example/>
      INSERT DATA {
          :three :child :two .
          :two :child :one .
          }
      

      This query using the + operator:

      PREFIX : <http://example/>
      SELECT *
        { ?s :child+ ?o }
      

      produced only two solutions, though it should have produced the transitive solution "http://example/three http://example/one" also:

      s	o
      http://example/two	http://example/one
      http://example/three	http://example/two
      

      This query using the {n} operator:

      PREFIX : <http://example/>
      SELECT *
        { ?s :child{2} ?o }
      
      

      produced these incorrect results, apparently ignoring the "{2}":

      s	o
      http://example/two	http://example/one
      http://example/three	http://example/two
      

      This query using the "/" operator:

      PREFIX : <http://example/>
      SELECT *
        { ?s :child / :child ?o }
      

      produced these incorrect results, apparently ignoring the "/ :child":

      s	o
      http://example/two	http://example/one
      http://example/three	http://example/two
      

      Finally, this query without any property path operator worked correctly:

      PREFIX : <http://example/>
      SELECT *
        { ?s :child ?o1 .  ?o1 :child ?o2 }
      

      producing this (correct) result:

      s	o1	o2
      http://example/three	http://example/two	http://example/one
      

      I did not test other property path features.

        Activity

        Hide
        bryanthompson bryanthompson added a comment -

        Property paths are not supported in this release. They will probably be in 1.3. That is the only remaining feature which has not yet been implemented from SPARQL 1.1.

        Thanks,
        Bryan

        Show
        bryanthompson bryanthompson added a comment - Property paths are not supported in this release. They will probably be in 1.3. That is the only remaining feature which has not yet been implemented from SPARQL 1.1. Thanks, Bryan
        Hide
        bryanthompson bryanthompson added a comment -

        This is a duplicate. See https://sourceforge.net/apps/trac/bigdata/ticket/495 (SPARQL 1.1 Property paths).

        We have also been looking at accelerated techniques for computing shortest paths. This would require an additional index data structure but it would provide real time shortest paths. We would probably want to extend the property paths notation to allow people to access the path itself, not just the head and tail. The technique that we are considering can actually produce paths in (approximately) increasing path length in real time. However, there is substantial additional data which needs to be maintained in order to accelerate the shortest path computation.

        Show
        bryanthompson bryanthompson added a comment - This is a duplicate. See https://sourceforge.net/apps/trac/bigdata/ticket/495 (SPARQL 1.1 Property paths). We have also been looking at accelerated techniques for computing shortest paths. This would require an additional index data structure but it would provide real time shortest paths. We would probably want to extend the property paths notation to allow people to access the path itself, not just the head and tail. The technique that we are considering can actually produce paths in (approximately) increasing path length in real time. However, there is substantial additional data which needs to be maintained in order to accelerate the shortest path computation.
        Hide
        bryanthompson bryanthompson added a comment -

        Property path support is available in 1.2.3.

        Show
        bryanthompson bryanthompson added a comment - Property path support is available in 1.2.3.

          People

          • Assignee:
            mikepersonick mikepersonick
            Reporter:
            dbooth-boston dbooth-boston
          • Votes:
            0 Vote for this issue
            Watchers:
            0 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved: