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DataObjects-backed repositories for RDF.rb

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DataObjects-backed RDF.rb repository, aiming for a simple use case and currently targeting SQLite and Postgres.

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This was written for a tutorial, and is thus a pretty naive implementation so far. RDF::DataObjects stores triples in a simple subject, predicate, object, context table. Don't try to back a big website with it yet. Nonetheless, it works, and it passes all its tests on Heroku as well.


repository = "sqlite3:test.db"
repository.count              #=> 1

You can use any DataObjects compatible connection options to create a new repository, but only SQLite3 and Postgres are implemented for now. The different databases are just different enough with their handling of unique constraints that some database-specific work is required for a new adapter, but it's not much.


The greatly preferred installation method is via RubyGems:

$ sudo gem install rdf-do

Requires Ruby >= 1.9.2


require 'rdf'
require 'rdf/do'
require 'do_postgres' # gem install do_postgres
require 'do_sqlite3'  # gem install do_sqlite3
repo = "postgres://localhost/database"
repo = "sqlite3:test.db"


Your repository is a fully-functional RDF.rb RDF::Repository. As with any RDF.rb repository, this includes the mixins RDF::Enumerable, RDF::Mutable, RDF::Durable, and RDF::Queryable. Please see for more information.


require 'rdf'
require 'rdf/ntriples'
require 'data_objects'
require 'do_sqlite3'
require 'rdf/do'

repo ='sqlite3:test.db')
# repo = 'postgres://postgres@server/database'
# heroku_repo =['DATABASE_URL'])

# How many statements did we have?
#=> 10

# Get the URI of the first subject
jhacker = repo.first.subject
#=> #<RDF::URI(>

# Delete everything to do with it
jhacker_statements = repo.query(:subject => jhacker) 
repo.delete *jhacker_statements
#=> 7

# with Postgres, we could have done this, but SQLite gives us a locking error:
# repo.delete(*repo.query(:subject => jhacker))

# Changed our mind--bring it back
repo.insert *jhacker_statements
#=> 10


This repository uses Git Flow to mange development and release activity. All submissions must be on a feature branch based on the develop branch to ease staging and integration.


The preferred method to report issues is the issue queue at You'll get the the most attention if you submit a failing test for a bug, or a pending test for a feature.

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