Schema Mapping & Conversion
While some folks design starting from RDF Schema and OWL, most applications in the Semantic Web will be derived from existing schemas and classes.Relational Databases
Relational Databases on the Semantic Web
Relational OWL
Relational OWL is an OSS (GPL) Java application that converts relational database schemas to RDF/OWL. The conversion seems pretty one-to-one to me, so I'm not sure what the OWL is needed for. Also they need to connect to the database JDBC rather than just reading a SQL Schema.Relational
OWL Home Page
Relational OWL SF Project Page
SquirrelRDF
SquirrelRDF is SPARQL server (using Jena) that supports querying most any datasource, and includes drivers for relational databases (via JDBC) and LDAP.http://jena.sourceforge.net/SquirrelRDF/
D2R MAP
http://www.wiwiss.fu-berlin.de/suhl/bizer/d2rmap/D2Rmap.htm
http://www.wiwiss.fu-berlin.de/suhl/bizer/D2RQ/
http://www.wiwiss.fu-berlin.de/suhl/ueber_uns/team/chris_bizer.htm
Open Source SQL Schemas
There are many interesting database schemas and datasets to mine out there.The SDSS (Sloan Digital Sky
Survey) has
their schema browsable here: http://cas.sdss.org/dr5/en/help/browser/browser.asp.
XML Schema
http://ofbiz.apache.org/documents.html
Java Classes
http://rdfx.org/schema/2004/10/19-java
UML
http://www-db.stanford.edu/~melnik/rdf/uml/
.NET
LISP
Atom
http://djpowell.net/blog/entries/Atom-RDF.html