See you in Boston for ISWC 2012!

The demo for ISWC went through! We will be having a stand during the demo session of ISWC 2012 in Boston!

This will be a great opportunity to have discussion on OBDA, mappings and projects. If you would like to meet during that week, let us know! 

QuestOWL is now available

We are happy to announce the availability of the first public version of QuestOWL, a version of Quest that is compatible with the OWLAPI 3 and that lets you query the ontologies with mappings you create using Protege and -ontopPro- directly from Java.

Some of the features available in QuestOWL (in addition to the general Quest features) are:

• A simple JDBC-like interface for connections and queries 
• OWLAPI compatible resultsets 
• Possibility to generate N-triple files and OWL ABox assertions out of mappings

The file is available in the usual location.

Documentation

We also prepared several examples on how to configure and use Eclipse to program with QuestOWL. Check them out and and let us know what you think!

Cheers,
The -ontop- Team

Exciting news

There are a couple of things that will come in the next release(s) of Quest that have us so excited that I had to share them.

• New query rewriting algorithm (w.r.t. TBox). Yes, finally we are updating the query rewriting algorithm with a totally different one that goes perfect with the rest of the optimisations we have (both in classic ABox mode and virtual ABox mode. As you have seen already, Quest is generally able to produce VERY small SQL queries, often one single SQL query thanks to the way it optimises mappings and how it stores ABox assertions (semantic indexes). However, in some cases generation of SQL takes some couple of seconds, in heavy cases up to a minute. This is due to a very outdated TBox query rewriter. With the new rewriting algorithm there won't be anymore waiting. The basic implementation is already done and the results are amazing, the same simple SQL query, but now in milliseconds/nanoseconds instead of seconds/minutes. With a bit more testing we will incorporate this in the next build.
• New mapping assistant and mapping extractor. Yes! finally some help in the mapping process, which right now is very painfull. The new automated extractor will be conformant with the Direct Mapping specification from the RDB2RDF recommendation (this one is half way done). The mapping assistant (in development by Josef) will be a manual, but will speed up mapping development by reducing it to a bunch of points and clicks. Of course, free mappings will still be available as before.

Stay tuned! Nice things are coming!

We are pleased to announce the availability of new material. Today we have made available:

• A demonstration video [1] that shows the basics of -ontopPro- and Quest in 'virtual RDF' or 'virtual ABox' mode. We show how ontologies with mappings work as well as the performance you can get using Quest over a large Postgres database.
• A Protege 4.2 bundle that includes -ontopPro- [2]. This will save you some time when installing -ontopPro-, only unzip and its ready.
• H2 stand-alone server with all tutorial databases [2]. H2 is a super-light Java-only database that can be run from a single file. We made a zip with H2 and that includes all the databases you need for the tutorials. You won't need to install Postgres or MySQL to experiment with -ontopPro- or Quest.

We are also restructuring and updating our documentation, we will announce new material as soon as it is available.

Cheers,
The -ontop- Team    

p.s. Please let us know if you have any questions regarding the new material or if you would like to see material on some particular topic. We will try to fix/update/add based on your requests.

[1] http://www.youtube.com/watch?v=KHtlARfex4c
[2] Available at our usual download site

New build is now available

We are pleased to announce that v1.7-alpha build 1692 of -ontop- is now available for download.

The highlights of this build are:

• ontopPro now supports for Protege 4.2 
• Quest now supports LIMIT, OFFSET and ORDER BY in SPARQL queries
• Better SQL optimization in case of redundant JOINs and queries (less redundancy and simpler queries) which yields improved query execution performance.          
• Improved support for SQL parsing

Moreover, the protege plugin was extended with many GUI improvements, e.g., better GUI navigation, shortcuts, etc. And last, we worked a lot on improving error management and error reporting in this build. We are sure you will find this build even more stable than before. The full changelog can be found here [1].

Demo

An online demo video of -ontopPro- and Quest in virtual ABox mode can be found at [2].

Performance and Benchmarks

We would like share some exciting news. Our colleagues in Manchester benchmarked Quest in 'virtual ABox mode' (with MySQL as backend) against Virtuoso and MySQL in a very large data set. The results are currently under revision for publication and are very encouraging. They confirmed that in many cases, Quest is able to provide much better performance than Virtuoso, usually 6-10 times faster than Virtuoso, and up to 500 times faster in extreme cases. They also found that our performance is almost as good as using MySQL directly, which means that both, the SQL queries we generate are in many cases already optimal. We will put a link to their paper in our website as soon as the publication is officially out.

Next steps

The next release of the system will include two major new features. First we will finally allow for OPTIONAL in SPARQL queries, taking us closer to a full SPARQL 1.0 implementation (only unbound predicates will be missing, and will follow shortly). Second, we will include new 'Mapping Assistant' and 'Automated Mapping' features in -ontopPro- that will help you speed up the mapping development process.


Best regards,
The -ontop- Team

[1] https://babbage.inf.unibz.it/trac/obdapublic/wiki/ObdalibPluginChangeLog 
[2] http://obda.inf.unibz.it/protege-plugin/




                                                 

Demonstration Video

We just uploaded a demo video about Quest in virtual ABox mode. The video explains some of the advantages of doing SPARQL query answering with Quest in virtual mode and it also explains the meaning of the mappings. We use -ontopPro- to show show to create mappings in a scenario based on the SQL version of IMDB.


The embedded version (its better to watch in fullscreen):