Ошибка
SQL-запрос:

--
-- Ограничения внешнего ключа таблицы `elements`
--
ALTER TABLE  `elements` ADD CONSTRAINT  `fk_elements_languages` FOREIGN KEY (  `id_lang` ) REFERENCES  `languages` (  `id` ) ON DELETE NO ACTION ON UPDATE NO ACTION ,
ADD CONSTRAINT  `fk_elements_objects` FOREIGN KEY (  `id_obj` ) REFERENCES  `objects` (  `id` ) ON DELETE NO ACTION ON UPDATE NO ACTION ,
ADD CONSTRAINT  `fk_elements_templates` FOREIGN KEY (  `id_tpl` ) REFERENCES  `templates` (  `id` ) ON DELETE NO ACTION ON UPDATE NO ACTION ,
ADD CONSTRAINT  `fk_elements_types` FOREIGN KEY (  `id_type` ) REFERENCES  `element_types` (  `id` ) ON DELETE NO ACTION ON UPDATE NO ACTION ,
ADD CONSTRAINT  `fk_element_menu` FOREIGN KEY (  `id_menu` ) REFERENCES  `objects` (  `id` ) ON DELETE SET NULL ON UPDATE CASCADE ,
ADD CONSTRAINT  `fk_element_parent` FOREIGN KEY (  `id_parent` ) REFERENCES  `elements` (  `id` ) ON DELETE NO ACTION ON UPDATE NO ACTION ;

Ответ MySQL: Документация

#1452 - Cannot add or update a child row: a foreign key constraint fails (`patriciy`.<result 2 when explaining filename '#sql-57c_eda80'>, CONSTRAINT `fk_elements_templates` FOREIGN KEY (`id_tpl`) REFERENCES `templates` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION)