W3C home > Mailing lists > Public > public-rdf-ruby@w3.org > February 2011

Issue with Spira has_many

From: Greg Lappen <greg@lapcominc.com>
Date: Tue, 1 Feb 2011 14:49:26 -0500
Message-ID: <AANLkTimLjGKDBwAVrQUHV3GSxsjC+YBxH4qG43nmZ-_O@mail.gmail.com>
To: public-rdf-ruby@w3.org
Hello again everyone,

I am now attempting to do some integration of RDF with our Ruby on Rails
application, and found the Spira project which I have to say is just awesome
- it's a perfect fit for what we want to do.  I'm having a small problem
though with getting relationships between our Spira resources to work.  I
basically have one class, and it is going to "have many" of another class.
 The subject matter happens to be SKOS concept and concept schemes.  Here's
the basic code:

in app/models/open_media/schema/skos/concept.rb:

class OpenMedia::Schema::SKOS::Concept
  include Spira::Resource

  default_source :types
  base_uri "http://data.openmedia.org/"
  type SKOS.Concept

  property :label, :predicate=>SKOS.label, :type=>XSD.string
end

in app/models/open_media/schema/skos/concept_scheme.rb:

class OpenMedia::Schema::SKOS::ConceptScheme
  include Spira::Resource

  default_source :types
  base_uri "http://data.openmedia.org/"
  type SKOS.ConceptScheme

  property :label, :predicate=>SKOS.prefLabel, :type=>XSD.string
  has_many :top_concepts, :predicate=>SKOS.hasTopConcept, :type=>:Concept
end

So with the has_many type being the symbol :Concept, I get the following
error:

ArgumentError: OpenMedia::Schema::SKOS is not missing constant Concept!
from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:479:in
`load_missing_constant'
 from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:183:in
`const_missing'
from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:181:in
`each'
 from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:181:in
`const_missing'
from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/spira-0.0.11/lib/spira/resource/dsl.rb:209:in
`const_get'
 from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/spira-0.0.11/lib/spira/resource/dsl.rb:209:in
`qualified_const_get'
from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/rdf-0.3.1/lib/rdf/ntriples/reader.rb:184:in
`inject'
 from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/spira-0.0.11/lib/spira/resource/dsl.rb:209:in
`each'
from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/spira-0.0.11/lib/spira/resource/dsl.rb:209:in
`inject'
 from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/spira-0.0.11/lib/spira/resource/dsl.rb:209:in
`qualified_const_get'
from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/spira-0.0.11/lib/spira/resource/dsl.rb:178:in
`classize_resource'
 from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/spira-0.0.11/lib/spira/resource/dsl.rb:142:in
`build_value'
from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/spira-0.0.11/lib/spira/resource/instance_methods.rb:91:in
`reload_attributes'
 from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/rdf-0.3.1/lib/rdf/mixin/queryable.rb:70:in
`each'
from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/rdf-0.3.1/lib/rdf/mixin/queryable.rb:70:in
`grep'
 from /Users/greg/.rvm/gems/ree-1.8.7-2010.02@openmedia/gems/rdf-0.3.1/lib/rdf/mixin/queryable.rb:70:in
`each'

Without the relationship between them, both classes work great.  Am I right
in thinking it's a disagreement between Rails class loading mechanism and
how Spira is trying to load the has_many type?  I can reference
OpenMedia::Schema::SKOS::Concept fine in rails console, but as soon as I
save the concept scheme with a concept in the has_many, I get this error.
 Any ideas?  I was prepared to fix this and submit a patch, but an hour
later, no such luch.  Thanks!

Greg
Received on Tuesday, 1 February 2011 19:50:19 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 1 February 2011 19:50:19 GMT