OntoGrate Online Service

Quering Relational Database with Semantic Web Ontologies

Introduction    |    Try it!    |    References


Querying is one of the key tasks of the Semantic Web. Although more and more Semantic Web data (e.g., RDF and OWL files) are being created, it is still necessary to support querying of existing relational databases, which are some of the largest data resources in the real world. It is not efficient to annotate all relational data into RDF/OWL triples and query them using OWL-based reasoning, which is known to be at least as hard as Nexptime. In this project, we use the online service of an ontology-based information integration system (OntoGrate) to query sales databases. The query can be written in OWL-QL and defined by existing OWL ontologies.

We use Order (OWL) as query ontology, which is about e-commerce (customers, orders, items, etc.) Stores7 from IBM Informix is our target relational database, which is defined by Stores7 Schema. Also, we can use our internal ontology language, Web-PDDL, to represent the Order Ontology and the Stores7 Ontology. The mapping between them (providing a unified view) is called a merged ontology and is also available for Stores7-Order.

Please try OntoGrate below.

For more information, please read our publications referenced below.

Back to top «

You also can try another online service of ontoGrate, which integrates databases using ontologies.

Try it!

OntoGrate is flexible. Suppose a Semantic Web agent wants to use the Order ontology to issue a query to find answers from the Stores7 database.

Here are some examples. You can copy and modify the OWL-QL queryPattern section of each example to the textarea below to try the Ontograte.

Source Ontology (i.e., what OWL ontology is used to specify the query?):

Target Database (i.e., from what database will the data come from?):

Namespace Prefixs:
owl-ql: http://www.w3.org/2003/10/owl-ql-syntax
rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns
order: http://www.dayf.de/2004/owl/order.owl

Query (the queryPattern section):

Back to top «


Back to top «
Last updated: 2010/04/06