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 This is due to a very outdated TBox query rewriter.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):

Delay longer than expected

We are a bit behind the schedule, but we will release the new build shortly. Sorry for the inconvenience ;)

Release delayed one week

We will have a small delay on the release that's scheduled for this week. We will postpone it until next week to be able to clean some last minute issues. Stay tuned! this release is packed with goodies, including Protege 4.2 support, support for LIMIT, OFFSET, ORDER BY and many other things!

v1.7-alpha-b1529 is now available

A new build for v1.7-alpha is now available. This time we focused on improving user interaction and solving important bugs/issues related to stability and we are happy to say that this is our most stable and user-friendly build to the date.

Highlights of this new build include:

• Improved error reporting and error message in Quest
• Improved syntax error reporting and messages in the mapping editor of -ontopPro-
• Fixed critical stability issue that triggered an endless loop of error dialogs in Protege 4.1
• Better layout, improved fonts and other GUI enhancements.

For a detailed description see our changelog.

As a hint to whats coming on the next release:

• Quest support for LIMIT, OFFSET and ORDER BY in SPARQL queries.
• Extending FILTER functions
• First release of the QuestOWL and -ontop- for OWL, the OWLAPI 3 libraries that will allow you to use Quest and -ontop- directly from Java, using the OWLAPI 3.