Hi, folks!
I''m trying to model the following kind of relationship in my
application:
Each Topic has many related Topics. The relationship is characterised
by "similarity" parameter.
That''s what I have in DB:
create_table "topics" do |t|
t.column "name" :string
end
create_table "related_topics" do |t|
t.column "topic_id", :integer, :null => false
t.column "related_topic_id", :integer, :null => false
t.column "similarity" :integer
end
and in the model:
class Topic < ActiveRecord::Base
has_and_belongs_to_many :related_topics,
:class_name => "Topic",
:join_table => "related_topics",
:association_foreign_key => "related_topic_id",
:foreign_key => "topic_id"
What is bad about this reference is that the similarity parameter is
unaccessible!
I can''t affect it neither during <<''ing of
related_topics, or any other
way.
E.g. when I do:
tp = Topic.find(1)
tp.related_topics.find(1).similarity = 5
tp.save
the similarity does not save.
I guess I should use join models and :through, but I have no idea how
to access similarity parameter in that case as well.
Please point me at any solutions to the problem. Thank you.
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this sounds like a job for a "has_many :through =>" association read this blog post on self-referential has_many :through associations, i think its quite exactly what you need. This blog covers other related_topics ( lol ) about this as well, have fun http://blog.hasmanythrough.com/articles/2006/04/21/self-referential-through --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Thorsten, thanks for your answer. I''ve tried this approach, but I can''t modify the "similarity" parameter anyway. If you look, Josh also has a "flow" parameter for his graphs - it''s exactly the same (in terms of db organization), what I want. But unfortunately, he writes nothing about flow''s further fate. So, still looking for the solution. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---