Why is there a global cataclysm of a personal and non-professional nature when creating connections?

Question

MySQL

two tables. Vacancies AND responses Associate

id (PK, unique)
AND in responses id_vac(index)

Fields converted to InnoDB.
Gives an error of a personal, non-professional nature.


As a matter of fact

ALTER TABLE `response` ADD FOREIGN KEY ( `vac_id` ) REFERENCES `vacancies` (`id`) ON DELETE CASCADE ON UPDATE CASCADE ;

What is wrong and why does it refuse to create FK ?

Answer 1

referential integrity broken? are there response.vac_id values ​​that don't match in vacancies.id ?