public function many_to_many(Model $reference) { $columns1 = parent::findConstraitn('PrimaryKey')->getColumns(); $columns2 = $reference->findConstraitn('PrimaryKey')->getColumns(); $mtm = ManyToMany::getInstance(parent::persistence(), $reference->persistence(), $columns1, $columns2); $this->weaks_entitys[get_class($mtm)] = $mtm; }