data relation in a single table with ORM / Annotation

quest.md

Data relation in a single table with ORM / Annotation

Assuming a courses table like this:

create table courses (
    course_id int primary key,
    course_name char(50)
  );

The PREREQUISITES table would look like this:

  create table prerequisites (
    course_id int references courses,
    prereq_course_id int references courses,
    primary key (course_id, prereq_course_id)
  );

but this does not comply with the organic generation of the tables in the ORM: An example is that in annotation relations are implemented with this syntax:

/**
 * @ORM\OneToMany(targetEntity="App\Entity\UserCertification", mappedBy="user")
 */
private $usercertification;

and then the command is run:

php bin/console doctrine:schema:update --force

and there are relationships or tables related to the following scheme:

DROP TABLE IF EXISTS `user_certification`;
CREATE TABLE IF NOT EXISTS `user_certification` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `certification` date NOT NULL,
  `expiration` date NOT NULL,
  `evaluation` int(11) NOT NULL,
  `user_id` int(11) DEFAULT NULL,
  `listcertification_id` int(11) DEFAULT NULL,
  `eventcertification_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `usercertification` (`id`,`certification`,`expiration`,`evaluation`),
  KEY `IDX_82B2C025A76ED395` (`user_id`),
  KEY `IDX_82B2C0255586BCD3` (`listcertification_id`),
  KEY `IDX_82B2C0257F4F8556` (`eventcertification_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

if I manually create the schema and then run this command to import the entities:

php bin/console doctrine:mapping:import "App\Entity" annotation --path=src/Entity

The result is this (it looks nothing like it):

    /**
     * @var int
     *
     * @ORM\Column(name="prereq_course_id", type="integer", nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="NONE")
     */
    private $prereqCourseId;

my doubt is what is the syntax for the relation expressed in the first two tables using the ORM / annotation instead of use the importation tool??

the scenario is as follows: I have a table with a list of courses ... but some of these courses have levels 1,2,3; then, in order to participate in the level 2 course, a prerequisite is required, which would be the previous level (1) ...

1. Basic First Aid.
2. Intermediate First Aid.
3. Advanced First Aid.

But I also have another scenario in the same table:

A "jungle survival" course may have prerequisites for courses such as "Intermediate First Aid", "Basic Telecommunications" and "rappelling for rescuers", in this case the requirements are not necessarily a previous level, they are simply requirements of previous courses.

So I thought that I would create a table to save the prerequisites but I don't quite understand how I should write the annotation of the ORM to generate said table and relation.

which looks nothing like onetomany or manytoone manual annotation

    /**
     * @var int
     *
     * @ORM\Column(name="prereq_course_id", type="integer", nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="NONE")
     */

When I generate it with import, it brings me something quite strange that does not resemble what is manually written.