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| author | José Mota <josemota.net@gmail.com> | 2012-04-06 19:40:37 +0100 |
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| committer | José Mota <josemota.net@gmail.com> | 2012-04-06 19:40:37 +0100 |
| commit | 3204575bfcd1f12db5945c8959073d40915cfdfe (patch) | |
| tree | 5b35a0896f91043c931482b5ecb99dc2aa154310 /_posts/2011-12-09-same-class-associations-in-rails-3.html | |
| parent | 6644e3213758ac5f8ea4f388d4dcf4105e7d4530 (diff) | |
Import all posts.
Diffstat (limited to '_posts/2011-12-09-same-class-associations-in-rails-3.html')
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diff --git a/_posts/2011-12-09-same-class-associations-in-rails-3.html b/_posts/2011-12-09-same-class-associations-in-rails-3.html new file mode 100644 index 0000000..654f69d --- /dev/null +++ b/_posts/2011-12-09-same-class-associations-in-rails-3.html @@ -0,0 +1,31 @@ +--- +layout: post +title: Same class associations in Rails 3 +tags: +- Development +status: publish +type: post +published: true +meta: + _edit_last: '1' + _cws_is_markdown: '1' +--- +<strong>[TL;DR]</strong> Even though the selected events conceptually belong to a record, the latter has the foreign keys to former. So technically, <code>has_one</code> is to be changed to <code>belongs_to</code>. + +<hr /> + +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. + +<h3>Context</h3> + +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 <code>id</code>'s in the record's table. + +<h3>So what did technically happen?</h3> + +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. + +<h3>Code sample</h3> + +[gist id=1449428] |