I want to write a web app with rails what uses RDF to represent linked data. But I really don't know what might be the best approach to store RDF graphs within a database for persistent storage. Also I want to use something like paper_trail to provide versioning database objects.
I read about RDF.rb and activeRDF. But RDF.rb does not include a layer to store data in a database. What about activeRDF?
I'm new to RDF. What is the best approach to handle large RDF graphs with rails?
Edit:
I found 4Store and AllegroGraph what fits for Ruby on Rails. I read that 4Store is entirely for free and AllegroGraph is limited to 50 million triples in the free version. What are the advantages of each of them?
Thanks.
Your database survey is quite incomplete. There is also BigData, OWLIM, Stardog, Virtuoso, Sesame, Mulgara, and TDB or SDB which are provided by Jena.
To clarify, Fuseki is just a server component for a backend that supports the Jena API to provide support for the SPARQL protocol. Generally, since you're using Ruby, this is how you will interact with a database -- via HTTP using SPARQL protocol. Probably every single database supports the SPARQL HTTP protocol for querying, and many will support something in the ballpark of either SPARQL update protocol, the graph store protocol, or a similar custom HTTP protocol for handling updates.
So if you're set on using Rails, then your best bet is to pick a database, work out a simple wrapper for the HTTP protocol, perhaps forking support in an existing Ruby library if it exists, and building your application based on that support.
Versioning is something that's not readily supported in a lot of systems. I think there is still a lot of thought going into how to do it properly in an RDF database. So likely, if you want versioning in your application, you're going to have to do something custom.