Injecting Linked Data into the Web has been a
major pain point for those who seek personal, service, or
organization-specific variants of DBpedia. Basically, the sequence goes
something like this:
- You encounter DBpedia or the LOD Cloud Pictorial.
- You look around (typically following your nose from link to
- You attempt to publish your own stuff.
- You get stuck.
The problems typically take the following form:
- Functionality confusion about the complementary Name and
Address functionality of a single URI abstraction
- Terminology confusion due to conflation and over-loading of
terms such as Resource, URL, Representation, Document, etc.
- Inability to find robust tools with which to generate Linked
Data from existing data sources such as
relational databases, CSV files, XML, Web Services, etc.
To start addressing these problems, here is a simple guide for
generating and publishing Linked Data using Virtuoso.
Step 1 - RDF Data Generation
Existing RDF data can be added to the Virtuoso RDF Quad Store
via a variety of built-in data loader utilities.
Many options allow you to easily and quickly generate RDF data
from other data sources:
- Install the Sponger Bookmarklet for the URIBurner
service. Bind this to your own SPARQL-compliant backend RDF database (in
this scenario, your local Virtuoso instance), and then Sponge some
- Convert relational DBMS data to RDF using the Virtuoso RDF
- Starting with CSV files, you can
- Place them at an HTTP-accessible location, and use the Virtuoso
Sponger to convert them to RDF or;
- Use the CVS import feature to import their content into
Virtuoso's relational data engine; then use the built-in RDF Views
Wizard as with other RDBMS data.
- Starting from XML files, you can
- Use Virtuoso's inbuilt XSLT-Processor for manual XML to RDF/XML
- Leverage the Sponger Cartridge for GRDDL, if there is a transformation service
associated with your XML data source, or;
- Let the Sponger analyze the XML data source and make a
best-effort transformation to RDF.
Step 2 - Linked Data Deployment
Install the Faceted Browser VAD package
fct_dav.vad) which delivers the following:
- Faceted Browser Engine UI
- Dynamic Hypermedia Resource Generator
- delivers descriptor resources for every entity (data object) in the Native or
Virtual Quad Stores
- supports a broad array of output formats, including
HTML+RDFa, RDF/XML, N3/Turtle, NTriples,
RDF-JSON, OData+Atom, and OData+JSON.
Step 3 - Linked Data Consumption & Exploitation
Three simple steps allow you, your enterprise, and your
customers to consume and exploit your newly deployed Linked Data
- Load a page like this in your browser:
<cname>[:<port>] gets replaced by the
host and port of your Virtuoso instance
<entity-uri> gets replaced by the URI you
want to see described -- for instance, the URI of one of the
resources you let the Sponger handle.
- Follow the links presented in the descriptor page.
- If you ever see a blank page with a hyperlink subject name in
the About: section at the top of the page, simply add the parameter
"&sp=1" to the URL in the browser's Address box, and hit
[ENTER]. This will result in an "on the fly" resource retrieval,
transformation, and descriptor page generation.
- Use the navigator controls to page up and down the data
associated with the "in scope" resource descriptor.
About this entry:
Author: Kingsley Uyi Idehen
Published: 10/29/2010 18:54 GMT-0500
Modified: 11/02/2010 11:55 GMT-0500
Tags: webservices , atom , rdf , xml , xslt , odbc , sql , linked_data , semanticweb , sparql , howto , virtuoso , DataSpace
Categories: Virtual Database ,
Data Access ,
SQL , Semantic Web , Web Services (Web 2.0) , Content Syndication
Comment Status: 0