title: Delta indexing the elastic search index on change of model's association record value change using Tire and Elastic Search
body: <p>I am a newbie to elastic Search and Tire in Ruby on Rails. Watched the railscasts from ryan bates and helped me to get going. Tire is a great gem and has functionality to delta indexing. Assuming i have a mapping like the following, will Tire automatically delta index the model associations if an association value is edited/ deleted. For Example, Assume i have index mapping like the following,</p>
  
  <pre><code> mapping do
      indexes :id,      :type =&gt; 'integer', :index    =&gt; :not_analyzed
      indexes :col_2,   :type =&gt; 'integer', :index    =&gt; :not_analyzed
      indexes :col_3,   :type =&gt; 'date'
      indexes :col_4,   :type =&gt; 'date'
  
      indexes :model_2 do
        indexes :name,                  :type =&gt; 'string', :analyzer =&gt; 'whitespace'
        indexes :association_col_2,     :type =&gt; 'string', :index    =&gt; :not_analyzed
      end
   end
  </code></pre>
  
  <p>When the value of model_2.association_col_2 changes will tire automatically delta index the corresponding row in the model defined the mapping for ? How should i approach delta indexing the model on association model value changes ?</p>
  
  <p>Thanks in advance</p>