Ultrawrap

[justin2004]

Just wanted to share this paper since the idea seems similar to semantic-sql:
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.259.2084&rep=rep1&type=pdf
"Ultrawrap: SPARQL Execution on Relational Data Technical Report"

"... comprises encoding a logical representation of the database as a graph using SQL views and a simple syntactic translation of SPARQL queries to SQL queries on those views"

I think Ultrawrap lead to https://gra.fo/.

[jamesaoverton]

Thanks, I hadn't heard of Ultrawrap. There's a number of SPARQL to SQL implementations out there, but I'm not aware of one that is (1) open, (2) maintained, and (3) performant. Does anybody have a good suggestion?

It should be possible to use the Linked Data Fragments approach with RDFTab: The LDF client breaks a SPARQL query down into a number of quad/triple queries, and it would be easy to serve these quads/triples from an RDFTab table. I haven't tried this yet. The overall approach deliberately sacrifices some query performance to reduce the computational load on the server.

R2RML is related, but I've had mixed experiences trying to use it. I just found RML which looks promising.

[justin2004]

there is https://ontop-vkg.org/ which uses R2RML mappings to do query answering (SPARQL to SQL).

RML looked promising to me too a few months ago until i tried to use it (with json sources). it has a number of limitations around jsonpath which made it not suitable for my team's needs. i noted some of those limitations and my alternative solution here: https://github.com/justin2004/rml-testing

[justin2004]

and here are some more SPARQL to SQL related tools:
https://github.com/semantalytics/awesome-semantic-web#rdb-to-rdf