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Posted to dev@jena.apache.org by "Stephen Allen (Created) (JIRA)" <ji...@apache.org> on 2012/04/02 04:54:28 UTC

[jira] [Created] (JENA-229) "SELECT DISTINCT * " produces duplicates when blank nodes are used the graph pattern

"SELECT DISTINCT * " produces duplicates when blank nodes are used the graph pattern
------------------------------------------------------------------------------------

                 Key: JENA-229
                 URL: https://issues.apache.org/jira/browse/JENA-229
             Project: Apache Jena
          Issue Type: Bug
          Components: ARQ
    Affects Versions: ARQ 2.9.0, ARQ 2.9.1
            Reporter: Stephen Allen
            Priority: Minor


When using a blank node in the graph pattern of a query, using "select distinct *" can result in duplicate rows.  There is a similar issue with "select reduced *"

Steps to reproduce:

1) Load the "books" database [1]
2) Add an additional statement [2]
3) Run the following query:
      PREFIX books:   <http://example.org/book/>
      PREFIX dc:      <http://purl.org/dc/elements/1.1/>
      select distinct *
      where {
        ?book dc:title ?title .
        ?book dc:creator [] .
      }

You see that you get a duplicate result for book5.

If you change the query to:
      PREFIX books:   <http://example.org/book/>
      PREFIX dc:      <http://purl.org/dc/elements/1.1/>
      select distinct ?book ?title
      where {
        ?book dc:title ?title .
        ?book dc:creator [] .
      }

You do not get duplicates.


[1] http://svn.apache.org/repos/asf/incubator/jena/Jena2/Fuseki/trunk/Data/books.ttl
[2] <http://example.org/book/book5> <http://purl.org/dc/elements/1.1/creator> "Sir Example" .



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[jira] [Commented] (JENA-229) "SELECT DISTINCT * " produces duplicates when blank nodes are used the graph pattern

Posted by "Andy Seaborne (Commented) (JIRA)" <ji...@apache.org>.
    [ https://issues.apache.org/jira/browse/JENA-229?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13244032#comment-13244032 ] 

Andy Seaborne commented on JENA-229:
------------------------------------

Is this JENA-211?

I tried to recreate this on the current development system but can't.

I don't get a duplicate with ARQ 2.9.1 / I do with ARQ 2.9.0.

What is the output of "arq.sparql --version" for the ARQ 2.9.1 you are using?

Simpler test case:
@prefix : <http://example/> .

:a :p :b .
:a :p :c .

Query:
SELECT DISTINCT * { ?a ?x [] }

I get different behavior between ARQ 2.9.0 (wrong) and current 2.9.1 (right).
(and ARQ 2.8.X's are wrong as well).
                
> "SELECT DISTINCT * " produces duplicates when blank nodes are used the graph pattern
> ------------------------------------------------------------------------------------
>
>                 Key: JENA-229
>                 URL: https://issues.apache.org/jira/browse/JENA-229
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: ARQ
>    Affects Versions: ARQ 2.9.0, ARQ 2.9.1
>            Reporter: Stephen Allen
>            Priority: Minor
>
> When using a blank node in the graph pattern of a query, using "select distinct *" can result in duplicate rows.  There is a similar issue with "select reduced *"
> Steps to reproduce:
> 1) Load the "books" database [1]
> 2) Add an additional statement [2]
> 3) Run the following query:
>       PREFIX books:   <http://example.org/book/>
>       PREFIX dc:      <http://purl.org/dc/elements/1.1/>
>       select distinct *
>       where {
>         ?book dc:title ?title .
>         ?book dc:creator [] .
>       }
> You see that you get a duplicate result for book5.
> If you change the query to:
>       PREFIX books:   <http://example.org/book/>
>       PREFIX dc:      <http://purl.org/dc/elements/1.1/>
>       select distinct ?book ?title
>       where {
>         ?book dc:title ?title .
>         ?book dc:creator [] .
>       }
> You do not get duplicates.
> [1] http://svn.apache.org/repos/asf/incubator/jena/Jena2/Fuseki/trunk/Data/books.ttl
> [2] <http://example.org/book/book5> <http://purl.org/dc/elements/1.1/creator> "Sir Example" .

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[jira] [Closed] (JENA-229) "SELECT DISTINCT * " produces duplicates when blank nodes are used the graph pattern

Posted by "Stephen Allen (Closed) (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/JENA-229?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Stephen Allen closed JENA-229.
------------------------------

       Resolution: Duplicate
    Fix Version/s: ARQ 2.9.1

Yes, this is a duplicate of JENA-211.  I erroneously thought I was testing against 2.9.1, when in fact I was using 2.9.0.  It works correctly in 2.9.1.
                
> "SELECT DISTINCT * " produces duplicates when blank nodes are used the graph pattern
> ------------------------------------------------------------------------------------
>
>                 Key: JENA-229
>                 URL: https://issues.apache.org/jira/browse/JENA-229
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: ARQ
>    Affects Versions: ARQ 2.9.0, ARQ 2.9.1
>            Reporter: Stephen Allen
>            Priority: Minor
>             Fix For: ARQ 2.9.1
>
>
> When using a blank node in the graph pattern of a query, using "select distinct *" can result in duplicate rows.  There is a similar issue with "select reduced *"
> Steps to reproduce:
> 1) Load the "books" database [1]
> 2) Add an additional statement [2]
> 3) Run the following query:
>       PREFIX books:   <http://example.org/book/>
>       PREFIX dc:      <http://purl.org/dc/elements/1.1/>
>       select distinct *
>       where {
>         ?book dc:title ?title .
>         ?book dc:creator [] .
>       }
> You see that you get a duplicate result for book5.
> If you change the query to:
>       PREFIX books:   <http://example.org/book/>
>       PREFIX dc:      <http://purl.org/dc/elements/1.1/>
>       select distinct ?book ?title
>       where {
>         ?book dc:title ?title .
>         ?book dc:creator [] .
>       }
> You do not get duplicates.
> [1] http://svn.apache.org/repos/asf/incubator/jena/Jena2/Fuseki/trunk/Data/books.ttl
> [2] <http://example.org/book/book5> <http://purl.org/dc/elements/1.1/creator> "Sir Example" .

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