title: Why can't i use functions like ->addAttributeToSort('name', 'ASC'); in my custom model?
body: <p>I had created a custom model which uses ORM, i tried out "Weblog" example in the link <a href="http://www.magentocommerce.com/knowledge-base/entry/magento-for-dev-part-5-magento-models-and-orm-basics" rel="nofollow">http://www.magentocommerce.com/knowledge-base/entry/magento-for-dev-part-5-magento-models-and-orm-basics</a> and i was able to retrieve values from db using collection, but i cannot use functions like "->addAttributeToSort('name', 'ASC');" with my collection object.</p>
  
  <p>Are these functions specific only to product model such as "catalog/product"? if so how could i use such filtering capabilities to my custom function?</p>
  
  <p>Thank you very much..!!</p>