title: .find or where condition in active record querying
body: <p>I am confused on where to use '.find' and where to use 'where'. is there a difference in the performance during the execution of the query ?? </p>
  
  <p>example : converted the existing queries which are using .find as below : </p>
  
  <p><code>FileOrFolder.find_by_fullpath(completePath, :select=&gt;"id")</code>   --></p>
  
  <pre><code>FileOrFolder.where(fullpath: completePath).select(:id).first
  </code></pre>
  
  <p><code>Component.find(:first, :conditions=&gt;["cluster_id = ? AND name = ?", cluster_id, key])</code>  --> </p>
  
  <pre><code>Component.where(cluster_id: cluster_id, name: key).first
  </code></pre>