DB_DataObject joinAdd question

Trying to get my use of joinadd correct: // so I set up my two objects $dboi = DB_DataObject::factory('item'); $dboc = DB_DataObject::factory('category'); // and join 'em together $dboi->joinadd($dboc); // I set up the first two where conditions $dboi->member_id = $member_id; $dboi->item_status = 'approved'; // And now I want to select on a column in category. // I tried $dboi->_dboc->item_class = $item_class // and a few other permutations, but finally wound up with: $dboi->whereadd("category.item_class = '$item_class'"); So was there something I could have done other than the whereadd? Note that I also have [item] category_id = category:category_id in my links file. Thanks, </edg>