SPARQL |The Semantic Puzzle

Greetings from Crete!

June 4, 2009 by Andreas Blumauer, Category: Conferences & Events

Michael Hausenblas & Chris Bizer

ESWC 2009 is not over yet – but I am happy to announce: The Semantic Web Community is more alive than ever before! We had four days of brilliant talks, vibrant meetings, and great atmosphere so far. Some highlights:

Chris Bizer presentation of Berlin SPARQL Benchmark (BSBM) or Enrico Minacks´s talk about benchmarking RDF stores showed that base technologies of the semantic web are mature enough for real-world applications.
Use cases from many domains like biodiversity, astronomy or multi-media showed clearly the trend that the semantic web becomes “ubiquitous” and has left the labs.
The idea of Linking (Open) Data became pre-dominant in the community, many projects are built around this infrastructure already. But there is a clear demand for improved ontology matching or brokering services like the recently released <sameAs>
Martin Hepp´s lightning talk about “What makes for a good ontology?” and emotional reactions from the audience on that showed, that grass-root approaches and top-down approaches for ontology building still haven´t grown together, but they are getting closer
Weather and food here in Crete is great!

Tim Berners-Lee: “We need data on the Web to work better together”

April 22, 2009 by Christoph Wieser, Category: Conferences & Events, Linked Data & Open Data

Today, the 18th WWW conference started in Madrid, Spain. In his opening talk, Tim Berners-Lee outlined the status quo of the current Web and focused on areas for ongoing research.

According to Tim Berners-Lee the Web is still static and consists mostly of archived HTML and PDF documents. There is still a need for a read/write Web and the standards are still not used to a sufficient extend. Changes in the Web are the ‘move to mobile’ and the climb up of ‘advertizing to being a science’.

Beside the still existing challenges of the current Web, additional ones arrived. Web Applications as well as Open Social Networking and Open Linked Data count to the area of current interest.

Web Applications are supposed to become new computing platforms and need a serious clean trust system. In the future Web Applications could offer a decentralized modular installation like a webized Debian.

Open Social Networking has become a great application in the Web. Currently it suffers from the ‘Social Silo Problem’. Users have often accounts in several platforms like Facebook or MySpace. The platforms, however, are separated from each other like in a field of silos. The challenge of the Semantic Web Community is now to interconnect the silos via RDF, OWL, HTTP, and SPARQL. A further requirement of Tim Berners-Lee are to focus on a Secure Web id.

Open Linked Data attracted the attention of Tim Berners-Lee most of all. Being one of the chairs of the co-located workshop ‘Linked Data on the Web’ he stressed that “we need data on the Web to work better together” in government, enterprise, and science. Open Linked Data could be a wizard for users of existing relational database systems. As query language he proposed a federated/delegated SPARQL.

Finally, Tim Berners-Lee described the role of researchers in those challenges. Researchers should ‘build a platform for others that follow’. Thereby, one should not assume what people will use the platform for.

(Report by Christoph Wieser / Salzburg Research)

Using Triplify to expose the semantics of a site

April 20, 2009 by Thomas Schandl, Category: Calls & Competitions, Linked Data & Open Data

Recently the SWC took a thorough look at Triplify, a tool for mapping the contents of a relational DB to RDF, in the course of which we could convince ourselves of Triplify’s ease of use and its potent capabilities.
We take this opportunity to given an account of the philosophy behind Triplify, how it is used and also had the chance to interview the creator Sören Auer.

A common objection from critics of the semantic web is that regular users or webmasters won’t go to the trouble of marking up their content or whole web sites with RDF.
While it is obvious that nobody is going to decorate their web pages with hand-carved RDF triples, it is also apparent that a lot of the current web’s pages are generated by transforming information from relational databases to HTML pages, which are perfectly suited for human consumption, but which suffer from a big loss of machine-readable semantics.

As the information in the relational databases is highly structured and contains rich semantics, it is only natural to also use the already existing structured data to generate RDF representations of the same information.

Triplify is all about this approach of bootstrapping data for the semantic web. It does this for web applications which are built on PHP and MySQL.
Triplify consists of a lightweight PHP script and a configuration file. The latter is used to do the mapping of the columns of an application’s relational database to appropriate RDF classes and properties.

In many cases a site administrator who wants to export her site’s content as RDF, only has to save Triplify with a premade configuration file for her site’s application into the right folder, as for many popular applications like WordPress, Joomla! or phpBB all the work has already been done.
Once installed, Triplify can be used to generate a dump of the site’s complete RDF graph, or to generate Linked Data, as each of the site’s main concepts’ RDF graph is provided under its own URL, e.g. the semantic description of a user with the ID 123 can be accessed under http://yoursite.com/triplify/user/123.

If no configuration for an application exits, it is fairly easy to create one by yourself.
All one has to do is to look at the app’s database schema, find appropriate classes and properties from well known ontologies and create MySQL queries that grab the data from the relational database and map them to RDF classes or properties.
An example for a query that takes the data from a table describing the user of a CMS:
"SELECT id, name AS 'foaf:name', url AS 'foaf:homepage', short_description AS 'dc:abstract' FROM user_table",

Triplify’s creator Sören Auer kindly gave us the opportunity for an interview:

Triplify is very easy to configure for web developers. For which scenarios would you recommend to use Triplify, and in which situations other approaches of semantifying your data might be more suitable?

As you already mentioned Triplify was primarily developed for Web applications developed in PHP. These usually have a relatively small and simple set of tables. Triplify creates complete RDF exports, Linked Data or JSON, but does not include SPARQL endpoint functionality. When SPARQL is required you are better off with D2R Server or Virtuosos RDF views.

Triplify creates semantic representations of the data in relational databases. Do you think there would also be benefit in the inverse approach i. e. creating an application that parses triples and writes it to a relational DB according to a mapping file?

In certain scenarios this might make sense, but for the most cases I think the database schema has to be developed separately. Database schemata contain more storage and retrieval oriented information, such as for example about data indexing. Vocabularies and ontologies on the other hand represent information on a conceptually higher level and are more flexible with regard to evolution of the information structures than databases.

Are there plans for further development of Triplify?

Sure. We want to add SPARQL support and possibly port Triplify to other scripting languages such as Ruby and Python.

Thank you Sören, we will stay tuned about the news from your great application and look forward to the Triplification Challenge 2009!

semantic technolgies for non-SQL-writers

January 30, 2009 by Thomas Thurner, Category: Tools & Software

isd_banner3 Andreas Blumauer (Semantic Web Company) talked with Brian Donnelly about a new system on the market called “Semantic Discovery System” (SDS), which helps to do sophisticated queries across existing datasets. Also talking why complex scripts or triple stores should not be exposed to the end-users anymore.

SDS is doing, what semantic web enterprises promised for years: An application that allows users to formulate sophisticated questions on their datasets and getting back data without writing SQL statements or going down to OWL concepts.

SDS leave the data in its orignal format and doing no transformation into triple stores. And then give the user through a graphical desktop software – with the use of OWL and SPARQL – the possibility to formulate questions on this datasets. So this is a software engine that focuses “at business people with a tool as easy to use as Excel or Mind Manager – with zero need to know or care about OWL, SPARQL” as Donnelly explains.

The next times will show if Donnelly’s “Semantic Discovery System” may be a semantic web killer application. In any case it seems to be a good step in bringing semantic technologies out of the teccie’s corner onto the desktops of business users.

Read the full interview at www.semantic-web.at

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