skeeks\cms\behaviors\RelationalBehavior::attach PHP Method

    public function attach($owner)
    {
        if (!$owner instanceof ActiveRecord) {
            throw new ErrorException(\Yii::t('skeeks/cms', 'Owner must be instance of {yii}', ['yii' => 'yii\\db\\ActiveRecord']));
        }
        if (count($owner->getTableSchema()->primaryKey) > 1) {
            throw new ErrorException(\Yii::t('skeeks/cms', 'RelationalBehavior doesn\'t support composite primary keys'));
        }
        parent::attach($owner);
    }