rdf-mongo :: MongoDB storage adapter for RDF.rb

This is an RDF.rb storage adapter for MongoDB.

See http://blog.datagraph.org/2010/04/rdf-repository-howto for an overview.

Versioning and backwards compatibility

Moving forward, the versioning will reflect the RDF.rb version number for which all rdf-specs are passing.

It should also be noted that prior to 1.0, there are no guarantees of backwards compatibility for data stored using previous versions of the gem. This is to make optimizing the schema for MongoDB easy.


You'll need the 'mongo', 'rdf', 'rdf-spec', and 'rspec' libraries. The easiest way to install these is via RubyGems.

$ sudo gem install mongo rdf rdf-spec rspec rdf-mongo

Implementation Notes

RDF Statements are stored as individual documents within MONGO using the following BSON:

  "s":  RDF::Value
  "st": one of :u or :n
  "p":  RDF::URI
  "pt": must be :n
  "o"   RDF::Value
  "ot"  one of :u, :n, :l, :ll, or :lt
  "ol"  Language symbol or RDF::URI
  "c"   RDF::Value or false
  "ct": one of :u, :n, :l, :ll, :lt or :default

An alternative that may be examined at a later point would be to use a representation based on RDF/JSON, or JSON-LD. This would save documents based on a common subject with one more more predicates having one or more types.


Please post questions or feedback to the W3C-ruby-rdf mailing list.


Thank you


MIT License