Bas van Westing wrote:
class Article < ActiveRecord::Base
has_many :readings
has_many :users, :through => :readings
end
class Reading < ActiveRecord::Base
belongs_to :article
belongs_to :user
end
Seems to me this is not the model you are seeking… perhaps this one:
class Article < ActiveRecord::Base
has_many :readings
end
class User < ActiveRecord::Base
has_many :readings
end
class Reading < ActiveRecord::Base
belongs_to :user # like a regular join table… but there are
benefits to making it a first class model
belongs_to :article
end
This makes sense to me, an article can be read by many users and a user
can read many articles making either a join table or a join model
necccessary…
if you just prefer the link table approach, you can go with this:
class Article < ActiveRecord::Base
has_and_belongs_to_many :users, :through=>:readings
end
class User < ActiveRecord::Base
has_and_belongs_to_many :articles, :through=>:readings
end # remember to set the link table “readings” id=>false in the
migration file
Now what I’m trying to do is:
article = Article.new
article.save!
user ids 1,2,3 exist in database, as does the article
article.user_ids = [ 1, 2, 3 ]
But I get the following error:
“undefined method `user_ids=’ for #Article:0x4aea69c”
Why isn’t the “user_ids=” method created?
Thanks,
Bas
with the above model approach, you can do
a = Article.create
3.times { a.readings << User.create } # let rails assign the ids… it’s
basically none of your bussiness outside of test cases… 
User.find(:all).count # => 3
or with the link table approach, you can do
a = Article.new
3.times {a.users << User.create}
none of the above code segments have been tested but it’s the general
idea…
hope this helps
ilan