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PORails or SQL to get through a few model associations
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5790090
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5791959
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CreationDate
2011-04-26T12:11:21.157
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2011-04-26T14:37:09.413
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2017-05-23T11:57:03.640
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text
Body
I'm a bit of a n00b when it comes to hacking my own SQL for my ruby on rails app, so your help would be much appreciated. I have a model as follows: <pre><code>Timetable has_many :enrollments Enrollment belongs_to :timetable belongs_to :stream has_one :course, :through => stream #Stream & Timetable together are unique for an Enrollment Stream has_many :enrollments belongs_to :course Course has_many :streams </code></pre> i.e <code>Timetable 1-* Enrollments *-1 Stream *-1 Course</code> I'm trying to find the best way to get a set of courses associated with a timetable, through it's enrollments, through each enrollment's streams, which have a course. Preferably something like: <pre><code>Timetable.courses </code></pre> Trying the following had no luck <pre><code>Timetable has_many :courses, :through => :enrollments, :source => :course </code></pre> It gave me an error <code>ActiveRecord::HasManyThroughSourceAssociationMacroError: Invalid source reflection macro :has_one :through for has_many :courses, :through => :enrollments. Use :source to specify the source reflection.</code> I took a look at <a href="https://stackoverflow.com/questions/1926536/invalid-source-reflection-macro-has-many-through">Invalid source reflection macro :has_many :through</a> and it seemed to be pretty close. I also found <a href="http://code.alexreisner.com/articles/has-many-through-habtm.html" rel="nofollow noreferrer">http://code.alexreisner.com/articles/has-many-through-habtm.html</a> but I can't quite grasp how to apply this here (although it is 12am NZT, so maybe that's why!). Help, hints or even the answer would be great!
Tags
<sql><ruby-on-rails>
Title
Rails or SQL to get through a few model associations
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1. PO
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 PTAnswer
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PostTypePostTypeId
1. PTQuestion
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1. USCommunity
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1. USNick Malcolm
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1. PL
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 LTLinked
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1. PO
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 PTAnswer
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1. VO
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 PORails or SQL to get through a few model associations
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 VTUpMod
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