public function setPositions($ids, $column, $start)
 {
     $model = $this->getOwner();
     $table = $model->tableName();
     $priorities = array();
     foreach ($ids as $id) {
         $priorities[$id] = $start--;
     }
     $case = SqlHelper::arrToCase('id', $priorities, $model->getTableAlias());
     $in = SqlHelper::in('id', $ids, $model->getTableAlias());
     $c = Yii::app()->db->commandBuilder->createSqlCommand("UPDATE {$table} AS t SET t.{$column} = {$case} WHERE {$in}");
     $c->execute();
 }