@Hashim in the future you should reply to the mailing list such that all
people can see your response and follow the thread. Now we can just see
your answer because James replied to you and the mailing list. We also
can't see your attachment.
Which paper are you talking about?
As James said, there is a difference between a syntax tree like the Jena
algebra tree does (without optimizations) and a query execution plan
(with optimizations).
Regarding LSQ, given that you're working at DICE group, I'd suggest to
have a look at it or simply talk to Saleem. But it does only extract the
"simple" features based on the syntax tree and makes it accessible as
RDF data itself.
Lorenz
On 20.09.23 23:05, James Anderson wrote:
good evening;
if you want to reproduce those results, you will have to examine the parsed
syntax tree.
that should comprise just two bgps, as that is the immediate syntax.
if, on the other hand, you examaine the results of a query planner, you are not
looking at a systax tree, you are looking at the query processor's prospective
exection plan.
execution model permits the transformations to which i alluded.
you will more likely get your desired representation by having jena emit an
sse, rather than an execution plan.
best regards, from berlin,
On 20. Sep 2023, at 17:48, Hashim Khan <[email protected]> wrote:
Thanks for the quick reply.
To be precise, I want to clarify the table on page 7 of the attached paper.
Here, the No. of BGPs is 2, and also some more values. I want to extract all
the info using Jena. But I could not till now. About the LSQ, I will check it,
but I am following this paper and want to reproduce the results.
Best Regards,
Hashim
On Tue, Sep 19, 2023 at 4:18 PM James Anderson <[email protected]>
wrote:
good afternoon;
you have to consider that a query processor is free to consolidate statement
patterns in a nominal bgp - which itself implicitly joins them, or separate
them in order to either apply a different join strategy or - as in this case,
to interleave an operation under the suspicion that it will reduce solution set
cardinality.
best regards, from berlin,
On 19. Sep 2023, at 13:20, Hashim Khan <[email protected]> wrote:
Hi,
Having a look on this SPARQL query:
---------------------------------------------------------------------------
prefix dbo:<http://dbpedia.org/ontology/>
prefix dbr:<http://dbpedia.org/resource/>
prefix foaf:<http://xmlns.com/foaf/0.1/>
SELECT DISTINCT ?name ?birth ?death
WHERE { ?person dbo:birthPlace dbr:Berlin .
?person dbo:birthDate ?birth .
?person foaf:name ?name .
OPTIONAL { ?person dbo:deathDate ?death . }
FILTER (?birth < "1900-01-01") .
}
LIMIT 100
-----------------------------------------------------------------------------
Using Apache Jena ARQ command, ./arq --query exampleQuery.sparql --explain
I got this result.
13:11:41 INFO exec :: ALGEBRA
(slice _ 100
(distinct
(project (?name ?birth ?death)
(conditional
(sequence
(filter (< ?birth "1900-01-01")
(bgp
(triple ?person <http://dbpedia.org/ontology/birthPlace> <
http://dbpedia.org/resource/Berlin>)
(triple ?person <http://dbpedia.org/ontology/birthDate>
?birth)
))
(bgp (triple ?person <http://xmlns.com/foaf/0.1/name> ?name)))
(bgp (triple ?person <http://dbpedia.org/ontology/deathDate>
?death))))))
13:11:41 INFO exec :: BGP
?person <http://dbpedia.org/ontology/birthPlace> <
http://dbpedia.org/resource/Berlin>
?person <http://dbpedia.org/ontology/birthDate> ?birth
13:11:41 INFO exec :: Reorder/generic
?person <http://dbpedia.org/ontology/birthPlace> <
http://dbpedia.org/resource/Berlin>
?person <http://dbpedia.org/ontology/birthDate> ?birth
13:11:41 INFO exec :: BGP :: ?person <
http://xmlns.com/foaf/0.1/name> ?name
------------------------
| name | birth | death |
========================
------------------------ I have a question about the Basic Graph Patterns.
I think, in this query there are two BGPs. But here i shows 3. Can anyone
explain it to me? Also, I want to know, the number of joins, no of
projection variables, number of left joins, depth, and such other relevant
info about the query features. How can I get all at one place?
Best Regards,
*Hashim Khan*
---
james anderson | [email protected] | https://dydra.com
--
Hashim Khan
<swj3336.pdf>
---
james anderson | [email protected] | https://dydra.com
--
Lorenz Bühmann
Research Associate/Scientific Developer
Email [email protected]
Institute for Applied Informatics e.V. (InfAI) | Goerdelerring 9 | 04109
Leipzig | Germany
