Rails - Dec 2006 - Active Record error with Association

I am learning to use ActiveRecord so bear with me. I have a script that
looks like this

class Product < ActiveRecord::Base
  set_primary_key "ProductID"
  set_table_name "Product"
  has_many :variants, :foreign_key => ''ProductID''
end

class Variant < ActiveRecord::Base
  set_primary_key "VariantID"
  set_table_name "ProductVariant"
  belongs_to :product, :foreign_key => ''ProductID''
  has_one :capacity, :foreign_key => ''CapacityID''
  has_one :material, :foreign_key => ''MaterialID''
end

class Capacity < ActiveRecord::Base
  set_primary_key "CapacityID"
  has_many :variants, :foreign_key => ''CapacityID''
end

class Material < ActiveRecord::Base
  set_primary_key "MaterialID"
  has_many :variants, :foreign_key => ''MaterialID''
end

widget = Product.find("10")
puts widget.Name
puts ''-------------------------------------''

widget.variants.each do |v|
  puts v.Name.squeeze(" ").chop!  + "\t\t In stock: \t" +
v.Inventory.to_s  + "\tPrice: \t" + v.Price.to_s + "\tCapacity:
\t" +
v.capacity.Name.to_s
  puts "\t Material: \t" + v.material.Name.to_s # this line breaks the
script

end

The "puts "\t Material: \t" + v.material.Name.to_s"  line in
the do
loop triggers the following error:

B2
-------------------------------------
654 - TB2 Cup & Bearin		 In stock: 	0	Price: 	80.0	Capacity: 	300 KG
ar4.rb:42: undefined method `Name'' for nil:NilClass (NoMethodError)
	from
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/associations/association_proxy.rb:110:in
`each''
	from
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/associations/association_proxy.rb:110:in
`send''
	from
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/associations/association_proxy.rb:110:in
`method_missing''
	from
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/associations/has_many_association.rb:90:in
`method_missing''
	from ar4.rb:40

The Materials table consists of two fields MaterialID, Name

Any ideas would be greatly appreciated.

thanks,

Luis


--~--~---------~--~----~------------~-------~--~----~
 You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---