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POWhy aren't Rails model attributes accessible using symbols instead of strings?
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  1. POWhy aren't Rails model attributes accessible using symbols instead of strings?
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    copied!<p>I need to compare some Rails (2.3.11) model attribute values before and after a database update, so I start by finding my record and saving the existing attribute values in a hash, as follows:</p> <pre><code>id = params[:id] work_effort = WorkEffort.find(id) ancestor_rollup_fields = { :scheduled_completion_date =&gt; work_effort.scheduled_completion_date } work_effort.update_attributes(params.except(:controller, :action)) #etcetera </code></pre> <p>Note I am adhering to the "best practice" of using a symbol for a hash key.</p> <p>Then I have a method that takes the model and the hash to determine possible additional steps to take if the values from the hash and the model attributes don't match. To determine this I tried to get at the model attribute value in an each loop but I was getting nil at first:</p> <pre><code>def rollup_ancestor_updates(work_effort, ancestor_rollup_fields) ancestor_rollup_fields.each do |key, value| model_val = work_effort.attributes[key] #nil #etcetera </code></pre> <p>In debugging the above I noticed that hard-coding a string as a key: </p> <pre><code>work_effort.attribute['scheduled_completion_date'] </code></pre> <p>Returned the desired value. So then in my each block I tried the following and it worked:</p> <pre><code>model_val = work_effort.attributes[key.to_s] </code></pre> <p>Is there a different way to do this? To me, with just 3 months Ruby/Rails experience, it's confusing to use symbols as hash keys as is the prescribed best practice, but then have to call .to_s on the symbol to get at a model attribute. Has anybody else experienced this, worked around this, been confused by this too? Thanks in advance</p>
 

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