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author | José Mota <josemota.net@gmail.com> | 2012-10-22 12:42:39 +0100 |
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committer | José Mota <josemota.net@gmail.com> | 2012-10-22 12:42:39 +0100 |
commit | 491f496a7143e70ba58cbf25d700267ac96783fa (patch) | |
tree | dac3161fb6f5b7601a5a928c8dad59a5ec501caa /_posts/2011-12-09-same-class-associations-in-rails-3.markdown | |
parent | 606a507fff5fc179764b8a0f5d26bc33334ebd86 (diff) |
Convert Rails 3 associations post to Markdown.
Diffstat (limited to '_posts/2011-12-09-same-class-associations-in-rails-3.markdown')
-rw-r--r-- | _posts/2011-12-09-same-class-associations-in-rails-3.markdown | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/_posts/2011-12-09-same-class-associations-in-rails-3.markdown b/_posts/2011-12-09-same-class-associations-in-rails-3.markdown new file mode 100644 index 0000000..e7062e4 --- /dev/null +++ b/_posts/2011-12-09-same-class-associations-in-rails-3.markdown @@ -0,0 +1,43 @@ +--- +layout: post +title: Same class associations in Rails 3 +tags: development +type: post +published: true +--- + +**[TL;DR]** Even though the selected events conceptually belong to a record, +the latter has the foreign keys to former. So technically, `has_one` +is to be changed to `belongs_to`. + +* * * + +This is the first time I've ran into something like this and it was interesting +to realize what it actually means when developing a business logic in Rails. + +### Context + +In this app I'm building, I have <em>Students</em> that have a <em>Record</em> +per year. Each record has several <em>Events</em>. These records also have two +specific events: a <em>test</em> and an <em>audition</em>, registered in the +schema as `id`'s in the record's table. + +### So what did technically happen? + +I wasn't able to access those specific events through the associations +specified in the model. Given <code>r = Record.first</code>, when I tried to +access the audition, by using <code>r.test</code>, Rails would use a SQL query +that would correspond to <code>r.events.first</code> instead. + +After acknowledging that, I turned to <a +href="http://twitter.com/varandas">@varandas</a> and we both thought it might +be a bug in the Rails framework. Turns out it wasn't; all I had to do was +switch from <code>has\_one</code> to <code>belongs\_to</code> (thanks <a + href="http://github.com/drogus">@drogus</a>!). The reason for that is the + foreign key is on the <code>records</code> table. From the framework's + perspective, it looks like the record actually <em>belongs to</em> the event, + when in practice it's not. + +### Code sample + +<script src="http://gist.github.com/1449428.js"></script> |