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POHow to add data to a newly created column in migration?
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  1. POHow to add data to a newly created column in migration?
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    copied!<p>In an already-deployed application, in my <code>seeds.rb</code>, I have the following:</p> <pre><code>State.create!(:state =&gt; "Alabama") State.create!(:state =&gt; "Delaware") ... </code></pre> <p>Now I wanted to add the two-letter code for each state.</p> <p>So I made a migration like this:</p> <pre><code>class AddStateCodeToStates &lt; ActiveRecord::Migration def self.up add_column :states, :state_code, :string update(&lt;&lt;-SQL UPDATE states SET state_code='WA' where state = 'Washington' SQL ) ...lots of these SQL statement... end def self.down end end </code></pre> <p><strong>Problem is:</strong></p> <p>In development environment, when I want to recreate the database from scratch, then after the migrations run, at that point the <code>seeds.rb</code> has not yet been run.</p> <p>So, the <code>UPDATE xxx</code> in the <code>AddStateCodeToStates</code> migration has no data to work with (<code>states</code> table is empty because the data will be populated from the <code>seeds.rb</code>), thus the <code>state_code</code> remains <code>NULL</code>.</p> <p>So my questions are (they are so related, so sorry for not asking them as each separate question):</p> <ol> <li>How do I populate the <code>state_codes</code> when recreating the database (after the <code>states</code> table has data in it)?</li> <li>How do I get the <code>state_codes</code> when <code>rake db:migrate</code> on the deployed app (<code>seeds.rb</code> does not run on <code>rake db:migrate</code>)</li> <li>Should I not have used <code>seeds.rb</code> in the first place (and instead put data into the migrations)?</li> </ol>
 

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