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RDF*/SPARQL* support? #955
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Since RDFLib has essentially 0 active developers and we don't even manage
to make a release - I don't see that as very likely :D
Unless someone contributes a very good PR !
- Gunnar
…On Thu, 6 Feb 2020 at 20:02, Boris Pelakh ***@***.***> wrote:
There is currently a W3C working group considering the adoption of Olaf
Hartig's work on RDF*/SPARQL* as a W3C standard (
http://olafhartig.de/files/Hartig_AMW2017_RDFStar.pdf). Several DB
vendors already support this syntax (Anzo, Stardog, Blazegraph), and others
are working on adding it as a feature. It provides a great bridge between
RDF and Property graphs.
Could this be possibly added to rdflib?
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@gromgull I am working on it! Hope to publish a branch next week. |
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@JervenBolleman that is fantastic, please let me know if you need a hand with testing. |
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The approach I am taking is by going the RDF* PG mode where <ex:p ex:y ex:z> asserts the triple and itself is a special BNode (basically a bnode with a derivable _:id) Which maps to reified statements. Has it's downsides but I think making RDF* a syntactic sugar is the way to go. At least with my limited skills. |
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Hi, just wanted to note that my slow progress is available here. I am however, having difficulty with the parser code. So I was very over optimistic on getting this work faster. |
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I am now into adding the new EmpTP nodes into the algebra. Recursive |
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Well "it works" now. PG mode, SPARQL only by translating the sparql* into a reification quad. |
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Great work here @JervenBolleman! We (my company) will likely be looking at RDF* soon for W3C graph work (GQL). |
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@nicholascar thank you. Still a lot of work to be done.
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Just want to share my progress. The parsing is done better now, and instead of hacking in support to the algebra it is now pushed down into the evaluation. However, I have not yet managed to get the evaluate to work nicely. It is natural to put it in the evalBGP part, but resolving an "EmbeddedTriple" to a series of Identifiers is quite painful there. I need to think a bit more. |
Approach is horrid though, and code is being executed in the wrong place.
…spot in the evaluate stack. However, functionality wise it is a step back. Commiting and pushing this to share the work so others can have a look.
… triple with a reification quad. Unfortunatly, the parser gives CompValue objects in the case where I expect URIRef. There is now one method in evaluate that needs to be overriden to generate the right logic. This method still needs to move to the graph so that optimized stores can be developed.
…gebra changes might still be required
…e compvalue's into URIRef etc. Now wired up, reveals a failing test
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Hi @JervenBolleman, I along with a group of students from IIIT Delhi ardently wish to contribute to this issue. We would like to get in contact with you soon if possible and would be very obliged if you could walk us through the work done so far. |
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@pragya16067 find my e-mail and contact me. |
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Hey @JervenBolleman, mailed! |
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Position paper on RDF*/SPARQL* at https://blog.liu.se/olafhartig/2019/01/10/position-statement-rdf-star-and-sparql-star/ |
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This preprint has a lot of details required for implementing. Includes the required changes to the grammar. |
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Thanks @JervenBolleman and @nicholascar. Will take a look! |
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Consider the alternate Turtle syntax proposal by Stardog (they seem to have implemented it already): https://www.stardog.com/blog/property-graphs-meet-stardog/ |
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Just for the record: another triple store that supports RDF* and SPARQL* now is Ontotext GraphDB (as of version 9.2); see http://graphdb.ontotext.com/documentation/9.2/free/devhub/rdf-sparql-star.html The main part of their implementation is within their GraphDB code base but some of the base stuff is in the underlying RDF4J library they are using internally. Another Java library that you may look at to get inspiration for adding RDF*/SPARQL* support in RDFLib is Apache Jena and the RDFTools library we have built on top if it. At the core, the object model of Jena has been extended with a class called Node_Triple that can be used in the Triple class. Also, there are grammars for Turtle* and for the SPARQL* syntax. |
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Hi @JervenBolleman and @nicholascar , we have tried to make some changes for making the SPARQL* recursive in nature. Kindly review it :) (PR Link - JervenBolleman#1 ) |
Approach is horrid though, and code is being executed in the wrong place.
…spot in the evaluate stack. However, functionality wise it is a step back. Commiting and pushing this to share the work so others can have a look.
… triple with a reification quad. Unfortunatly, the parser gives CompValue objects in the case where I expect URIRef. There is now one method in evaluate that needs to be overriden to generate the right logic. This method still needs to move to the graph so that optimized stores can be developed.
…gebra changes might still be required
…e compvalue's into URIRef etc. Now wired up, reveals a failing test
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Hi @JervenBolleman and @nicholascar, I have added support for parsing and querying on RDF* graphs via some additional wrapper functions in the RDF (Turtle) parser. |
Hi @nicholascar. I have added a PR (#1111) with my work on adding support for parsing RDF* graphs. Kindly review it :) Hope to hear from you soon. |
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Hi Guys, I am curious to know is there any update on this? Thanks! |
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Hi @alex-randles JervenBolleman reviewed the PR associated with this issue, #1111, so that's the latest direct work. The other maintainers and I are still performing a bunch of clean-up updates to the code base before an RDFlib 6.0.0 release - mainly reducing the number of small PRs and tidying up old functions - before we tackle this major enhancement. So we will linkey only get to directly focussing on this work in a couple of months however it would be great if you or others could review and comment on PR #1111. I think it will need updating and a bit of work to pass tests still, if the approach is deemed appropriate. |
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Hi All, part of the work is also waiting for the SPARQL* specifications to
be more solid.
Especially in regards to the BIND operator, which currently needs a lot of
work.
This is because BIND for triple patterns is quite different from the
current BIND implementation, and this is where I have not continued my work
at all.
i.e. BIND is a subselect/filter more than a function call/rename.
I think that it would also be very good to modularize the Query parsing so
that it is explicit if a Query is SPARQLstar or SPARQL11.
…On Wed, Sep 23, 2020 at 12:25 AM Nicholas Car ***@***.***> wrote:
Hi @alex-randles <https://github.com/alex-randles> JervenBolleman
reviewed the PR associated with this issue, #1111
<#1111>, so that's the latest direct
work.
The other maintainers and I are still performing a bunch of clean-up
updates to the code base before an RDFlib 6.0.0 release - mainly reducing
the number of small PRs and tidying up old functions - before we tackle
this major enhancement. So we will linkey only get to directly focussing on
this work in a couple of months however it would be great if you or others
could review and comment on PR #1111
<#1111>. I think it will need
updating and a bit of work to pass tests still, if the approach is deemed
appropriate.
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--
Jerven Bolleman
me@jerven.eu
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Are there rdf-star issues and/or mailing list posts for the considered blocking SPARQL* spec issue(s)? RDF*RDF*: RDF*, SPARQL*, N-Triples*, Turtle*
## RDF*
RDF*: RDF*, SPARQL*, N-Triples*, Turtle*
- Web: https://w3c.github.io/rdf-star/
- Src: https://github.com/w3c/rdf-star
- Issues: https://github.com/w3c/rdf-star/issues
- MailingList: https://lists.w3.org/Archives/Public/public-rdf-star/
- UseCases: https://w3c.github.io/rdf-star/UCR/rdf-star-ucr.html
- Spec: RDF*: https://w3c.github.io/rdf-star/rdf-star-cg-spec.html
- Spec: SPARQL*: https://w3c.github.io/rdf-star/tests/sparql/syntax/manifest.html
- Spec: RDF* Semantics: https://w3c.github.io/rdf-star/tests/semantics/manifest.html
- Spec: Turtle*: https://w3c.github.io/rdf-star/tests/turtle/syntax/manifest.html
- Spec: N-Triples*: https://w3c.github.io/rdf-star/tests/nt/syntax/manifest.html |
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Hi! Is there any progress on this? |
ghost
added
This issue was moved to a discussion.
You can continue the conversation there. Go to discussion →
There is currently a W3C working group considering the adoption of Olaf Hartig's work on RDF*/SPARQL* as a W3C standard (http://olafhartig.de/files/Hartig_AMW2017_RDFStar.pdf). Several DB vendors already support this syntax (Anzo, Stardog, Blazegraph), and others are working on adding it as a feature. It provides a great bridge between RDF and Property graphs.
Could this be possibly added to
rdflib?The text was updated successfully, but these errors were encountered: