
Ontop – A Virtual Knowledge Graph System - hmottestad
https://ontop-vkg.org
======
mark_l_watson
Looks interesting. Years ago, I experimented with the D2RQ project that does
something similar.

It would be interesting to see a benchmark with something like WikiData or
DBPedia converted to a relational database and compared with a RDF store like
Virtuoso. Compare query speed, memory use, and index size on disk. Also seeing
a comparison of bulk data load times.

Anyway, looks like a cool project!

~~~
jerven
The basic idea was done in a nice study by Orri Erling at the time working on
virtuoso (now Facebook presto). Which indeed shows the major benefits of
recovering a physical schema.

[http://www.www2015.it/documents/proceedings/proceedings/p864...](http://www.www2015.it/documents/proceedings/proceedings/p864.pdf)

------
hmottestad
Gives you unified access to all your data spread across all your relational
databases.

Supports: PostgreSQL, MySQL, SQL server, Oracle and DB2

Allows you to query across all these databases through a unified interface.
Supports reasoning to allow for concepts to be modelled differently in each
relational database, but be queried through a single model. This means that
developers higher up the food chain don't need to know that the old DB2
instance from 2005 that stores experimental turbine data uses a new table per
turbine while the new Oracle db uses a single table with column to specify the
turbine instead.

------
kendallgclark
Gotta say, Stardog's been shipping a virtualization-powered Knowledge Graph
platform since 2014...

~~~
hmottestad
I've always wondered if the Stardog implementation is based on the work done
by Ontop? I can see from the history of Ontop that they also have releases
dating back to 2014.

~~~
guohuixiao
Indeed, the first implementation of VKG in Stardog v4 in 2014 shipped with
Ontop v1.16. Since then, Ontop has evolved and it improved a lot in terms of
features and performance.

