- From: Sebastian Hellmann <kurzum@googlemail.com>
- Date: Sun, 09 Mar 2008 17:52:27 +0100
- To: public-xg-rdb2rdf@w3.org
Hello, my name is Sebastian Hellmann, I'm about to finish my Master and will be a PhD Student at the AKSW Group Leipzig [1], soon . I'm currently doing some research in the db2owl direction. I spent the last couple of days making a large list of literature concerning mapping and conversion, which could be of some use [2][Y][Z]. IMHO the standardization process can be divided in separate tasks, which clearly depend on the way the mapping/conversion will be used: 1. uni-directional mapping RDB2RDF/OWL One of the most often read sentences, I came across during research was: "There is a lot of information 'hidden' in relational databases." and it seemed that it often would be sufficient to reveal that data and pour it into the Semantic Web. This should be done with a very lightweight approach, so that the average MySQL admin can participate. If Jemima Kiss [3] is right and the Web 3.0 from a non-technical perspective is all about rank, recommendation and personalization, then it should be possible to connect EVERY Web account any person has with his other Web accounts. Ignoring the problems like trust/security/privacy on this issue, there should be a way a user can connect his identity on a phpbb forum [4] with his identity on answers.yahoo.com [5] with his identity on a self-knitted PHP-MySQL Web app of his friend. Although the charter of this group states that there should not be a default mapping, I actually think there should be at least a recommendation or best practice on how to map the basics, e.g. a table "user" to FOAF, or at least a selection of standard vocabularies[FOAF, SIOC] and LinkedData [DBpedia, product catalog, revyu] for this simple scenario. There are already some tools (possibly quite a few), that provide fast access and querying, i.e. D2R[6], SquirrelRDF[7] and Sören Auer's Triplify[8]. With a proper standardization these tools could go one simple step further, which would help achieving a critical mass for the Semantic Web. 2. merging/mapping one or several databases to one RDF/OWL Schema Providing basic CRUD operations, keeping the old database(s). Most of the problems and suggestions have been stated in an earlier post by Andrew Matthews: http://lists.w3.org/Archives/Public/public-xg-rdb2rdf/2008Mar/0005.html Tools I found for this: Dartgrid [9], Coma++[10] 3. converting a relational database to RDF/OWL, no RDB any more It would be beneficial for some applications, e.g. which have a strong need for structuring/reasoning, to completely migrate to RDF/OWL. So the question here should be how is information stored in RDB and how is it stored in Ontologies. The RelDB Scheme normally needs to be transformed by an engineer, because OWL can have richer schemes, like in Reverse Engineering to Object-oriented databases. The main issue here is maybe to help create a good ontology containing all nice/good information and not containing weakly defined/unclean information from the RDB. There is a paper from Beijing [11], which proposes 11 rules, which seem to make sense. (I could not find a link to the tool they write about, it is called CODE, please mail me, if you find it). At our group, we have an Ontology Enrichment Tool, i.e. Jens Lehmann's DL-Learner [12], which could be used to enrich an initial schema extracted from a RDB to ease the burden on an engineer. *** Basically I tried to give a quick overview of how I see the problems/tasks that are to face. I'm more interested in the 1. and the 3. part, because we are working on this in one way or another. One could argue though that this incubator group should be concerned with the 2nd part only, because the 1. part might be too easy and there will be a lot of tutorials for this all over the net, which will reach a consensus sooner or later all by themselves and (3.) any company who wants to engage in the 3. task will need help by a professional ontology engineer anyhow, making standardization unnecessary. Hope I could help at least with my literature list, Sebastian [1] http://aksw.org/About [2] http://bibsonomy.org/user/sebastian/dbowl [3] http://www.guardian.co.uk/media/2008/feb/04/web20 [4] http://www.phpbb.com/ [5] http://answers.yahoo.com/ [6] http://www4.wiwiss.fu-berlin.de/bizer/D2RQ/ [7] http://jena.sourceforge.net/SquirrelRDF/ [8] http://triplify.org/About [9] http://esw.w3.org/topic/DartGrid [10] http://dbs.uni-leipzig.de/de/Research/coma.html [11] http://dblp.uni-trier.de/db/conf/waim/waim2005.html#LiDW05 [12] http://aksw.org/Projects/DLLearner **not so useful due to amount: delicious links about everything I found: [Y] http://del.icio.us/kurzum/dbowl delicious links about implemented tools: [Z] http://del.icio.us/kurzum/dbowl%2Btools
Received on Monday, 10 March 2008 03:08:56 UTC