php - Yii - reacting to attribute model assignation -

i want following in yii:

when attribute `a` in model class `m` set, something. 

and tried using setter like: seta($value) it's not called since yii cactiverecord first detects if attribute exists in database (and assigns it) , if not exist in database (i.e. it's not table attribute) normal instance variable looked up. final fallback calling property accesor.

(edit - wrong resolution order: lookup seems first instance variable, attribute, , accessor - anyway, problem still same since accesor resolved if no database field exists name)

here it's shown internal mechanics of __set (and bit upper, __get).

question: how can invert order, @ least attribute? means: want capture database field edition setter seta($value), performing field assignation (i.e. actual $this->a, should done without falling in stack overflow error) inside seta method

a reasonable approach override cactiverecord::setattribute in model class behave way need to:

class m extends cactiverecord {   ....   public function setattribute($name,$value) {     if($name === 'a') {       ..     }      return parent::setattribute($name, $value);   }   .... }