D2RQ is an open source tool that allows accessing relational databases as virtual RDF graphs without replicating the data into a triplestore. It provides a mapping language to connect databases to ontologies and integrates with Apache Jena to process SPARQL queries over the databases. D2RQ also includes a server that publishes the database contents as browsable linked data through resolvable URIs and SPARQL endpoints.

1. D2RQ
ACCESS RDB AS VIRTUAL RDF
(LAGECY DATA MEETS THE GLOBAL DATASETS)

2. What can it Do ?
• Access RDB as RDF read only graphs.
• Access RDB without "REPLICATION" into Triplestore as RDF.
• Make your content available as RDF and exploit it with Linked Data
Methodologies.
• Its Open Source, having Apache License, Version 2.0
• Supports various DB vendors.

3. Features
• Query Non-RDF database using SPARQL
• Access the Content of non-RDF databases as Linked Data over the web.
This makes legacy data make sense.
• Helps in dumps creations in order to load data into the Triple stores.
• Helps in accessing Non-RDF databases or RDB using Apache-Jena.
• Provides an AJAX based Query Browser for Querying RDB using SPARQL.

4. Architecture
Taken from D2RQ website

5. What this Platform has for me/us?
• A mapping language which connects the RDB database with the existing set
of ontologies
• D2RQ Engine that integrates seamlessly with Apache Jena to process
SPARQL upon the RDB.
• D2RQ server which acts as a port for viewing Linked Data over the web.
• It also Provides SPARQL endpoint with AJAX enabled endpoint.

6. How does the mapping happen ?
• D2RQ has a Mapping Language that does direct mapping of the RDB to
RDF.
• D2RQ Provides a tool to generate a custom mapping for the above purpose.
• Mappings treat Database Tables as Classes and the Column name as the
Properties to the Classes.
• D2RQ also provides a bridge to map the individual to the Domain
Knowledge i.e Ontologies.

7. Features of D2RQ Server
• Gives you Browsable content in RDF format (Human Readable), through which
one can navigate
• Resolvable URI's
• Content Negotiation
• SPARQL endpoint explorer, Supports SPARQL1.1. Queries over SPARQL Protocol
• Can be configured to serve files stored in Databases CLOB/BLOB
• Serving Vocabulary
• Publishing Meta Data

8. Basic Architecture of how D2RQ fits in with
RDB

9. Databases Supported By D2RQ
• Oracle
• MySQL (Drivers are provided by D2RQ)
• PostgreSQL (Drivers are provided by D2RQ)
• SQL Server
• HSQLDB
• Interbase/Firebird
• ODBC Datasources (With help of ODBC-JDBC Bridge but has limitations)

10. Getting Started
• Download D2RQ
• Generate the Mapping file against a compatible Database
• There is a tool included that would generate mapping after throughly inspecting
your database
• Modify the mapping file if required
• Run the D2RQ server along with the Mapping file
• Thats DONE!!!
• Now SPARQL your RDB and get the results of your choice

11. Important Links
• D2RQ : http://d2rq.org/
• D2RQ Dowload : https://github.com/downloads/d2rq/d2rq/d2rq-0.8.1.zip
• D2RQ Mapping : http://d2rq.org/generate-mapping
• D2RQ Server : http://d2rq.org/d2r-server
• D2RQ Query : http://d2rq.org/d2r-query
• dump-rdf : http://d2rq.org/dump-rdf
• D2RQ + JenaAPI : http://d2rq.org/jena

12. Contact me
• LinkedIn : in.linkedin.com/in/shivkumargnesh
• Twitter : @shivkumarganesh
• Gmail : gshiv.sk@gmail.com
• Hotmail : shivkumar_srm@hotmail.com
• Skype : gshiv.sk

13. Thanks