Insert, Update and Delete Query in Joomla

Now its Insert, Update and Delete Query in Joomla,

For INSERT query in Joomla structure
$db = &JFactory::getDBO();
             $insert_query = "INSERT into #__TABLENAME(feild1,feild2) values('value1','value2') ";
             $db->setQuery( $insert_query );
             $db->query();

For UPDATE query in Joomla structure
             $update_query = "UPDATE #__TABLENAME SET feild1 = 'value1' ";
             $db->setQuery( $update_query );
             $db->query();

For DELETE query in Joomla structure
             $delete_query = "DELETE FROM #__TABLENAME WHERE feild1 = 'value1' ";
             $db->setQuery( $delete_query );
             $db->query();