title: How can I set a timestamp field with the "update" or "update_all" methods of ActiveRecord?
body: <p>This is a Rails 3 project.</p>
  
  <p>I just can't figure out how to do this. I have two columns:</p>
  
  <pre><code>last_migrated timestamp
  migration_message text
  </code></pre>
  
  <p>that I would like to update, with condition:</p>
  
  <pre><code>:subdomain =&gt; "someval"
  </code></pre>
  
  <p>and yet everything I have tried has failed. I have tried about every MyModel.update and MyModel.update_all variation I can think of. The documentation just is not penetrating my thick skull for some reason. Please help.</p>
  
  <p>To clarify, I want to use an AR method to do the following:</p>
  
  <pre><code>update brands
  set last_migrated = x,
      migration_message = y
  where subdomain = 'someval'
  </code></pre>