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POModel traversal in rails: from child to sibling's child
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Id
4061374
data
AcceptedAnswerId
4061989
AnswerCount
2
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2010-10-31T00:55:46.190
FavoriteCount
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2010-10-31T05:40:15.350
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text
Body
I have the following model: <pre><code>class Advisor < ActiveRecord::Base belongs_to :course end class Course < ActiveRecord::Base has_many :advisors has_many :sessions has_many :materials, :through=>:sessions end class Session < ActiveRecord::Base belongs_to :course has_many :materials end class Material < ActiveRecord::Base belongs_to :session end </code></pre> I.e., every advisor teaches one course, every course has sessions, and every session has materials. I want to traverse from an advisor to all the associated materials, i.e. something like: <code>Advisor.first.materials</code> I tried to do: <pre><code>class Advisor < ActiveRecord::Base belongs_to :course has_many :sessions, :through=>:course has_many :materials, :through=>:sessions end </code></pre> But it didn't work as it treated sessions as a many-to-many table: <code>Unknown column 'sessions.advisor_id' in 'where clause': SELECT 'material'.* FROM 'materials' INNER JOIN 'sessions' ON 'materials'.session_id = 'sessions'.id WHERE (('sessions'.advisor_id = 1))</code> I then tried to do: <pre><code>class Advisor < ActiveRecord::Base belongs_to :course has_many :materials, :through=>:course end </code></pre> In an attempt to have the association use the "materials" association in the "Course" model, but received: <pre><code>ActiveRecord::HasManyThroughSourceAssociationMacroError: Invalid source reflection on macro :has_many :through for has_many :materials, :through=>:sessions. Use :source to specify the source reflection. </code></pre> Tried to use "sessions" as the source which was a nice try but made me receive only the sessions rather than the materials. Any ideas if this is at all possible? I'm using Rails 2.3.8 (perhaps time to upgrade?) Thanks! Amit
Tags
<ruby-on-rails><activerecord><has-many-through>
Title
Model traversal in rails: from child to sibling's child
singulars
PostAcceptedAnswerId
1. PO
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 PTAnswer
PostParentId
1. This table or related slice is empty.
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1. PTQuestion
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1. This table or related slice is empty.
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1. USAmitA
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1. PO
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2. PO
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A row detail

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