/**
* @return array the validation rules.
*/
public function rules()
{
return array_merge(parent::rules(), [[['file'], 'file', 'maxFiles' => 5]]);
}
/**
* @return \yii\db\ActiveQuery
*/
public function getIdAdvertising()
{
return $this->hasOne(Advertisement::className(), ['id' => 'id_advertising']);
}