So, you took the red pill? You’re a full blown RESTafarian brother? Good news for you, then. You’ll understand linked data in less then 30sec. Ok. Step by step. REST, understood as a ‘set of constraints that inform an architecture’:
- Resource Identification
- Uniform Interface
- Self-Describing Messages
- Hypermedia Driving Application State
- Stateless Interactions
… and now read the linked data principles with your ‘REST goggles’ on:
- Use URIs as names for things
- Use HTTP URIs so that people can look up those names.
- When someone looks up a URI, provide useful information, using the standards (RDF, SPARQL)
- Include links to other URIs. so that they can discover more things.
In the linked data, we use HTTP URIs for everything. For documents, but also for concepts or real-world entities such as people. Linked data provides a uniform (read-only) interface through HTTP GET. The messages are self-describing through RDF and RDF-based vocabularies and through the last of the linked data principles, what we have in the LOD cloud is a highly connected (or: interlinked) system.
- Identify and name your resources (using HTTP URIs),
- design your representations (documents & data), and
- link the resources to each other.
The same actually happens when you publish linked data, with some simplifications: due to the read-only characteristic of linked data you only have to worry about one HTTP verb (GET) and with RDF as the unified data model (based on your preferences and needs) you pick one of the RDF serializations (preferably RDFa, as it nicely integrates with HTML and hence allows you to serve humans and programs). When you have your data in RDF (or so ;) you’ll mainly find yourself worrying how to interlink it with other data on the Web. But this really is a huge benefit – finally enabling to use the Web as one huge database.
As an aside: I’m aware of the fact that we still need to sort out some issues along the way, both in the academia and in practice. However, I encourage people in both camps (RESTful yadayada and Linked Data rogues) to look beyond one’s own nose and eventually understand that there is only one Web and we all ‘live’ in it ;)