Doctrine OneToMany and ManyToOne, how to write cascading deletion?

Question

symfony

I can not achieve in any way that when deleting one entity, the key in the entity associated with it is nullified. for example

/**  
     * @ORM\OneToMany(targetEntity="User", mappedBy="division")
     */
    private $users;

/**
     * @ORM\ManyToOne(targetEntity="Division", inversedBy="users")
     * @ORM\JoinColumn(name="division_id", referencedColumnName="id", onDelete="SET NULL")
     */
    private $division;

Those. I want that when Division is deleted, the user entity is not deleted, but its division_id key is reset to zero. And I can't beat it. If you write cascade={"remove"} from the OneToMany side, then all entities will be deleted, and this is not exactly what interests me. I hope someone will be able to suggest how this is properly organized at the level of doctrine? :(

Answer 1

onDelete and others in JoinColumn - executed on the database side
(Check the database for this value - 99% that the cascade operation for deletion hangs in the database itself)
cascade={...} This is a programmatic implementation of these events (Driven by doctrine)
In your case , even if you remove all the doctrine settings for cascading operations, I'm sure that the associated entity will still be deleted, so the doctrine has nothing to do with it.

Answer 2

class User {
     /**  
     * @ORM\OneToMany(targetEntity="Division", mappedBy="division")
     */
    private $users;
}

class Division {
     /**
     * @ORM\ManyToOne(targetEntity="User", inversedBy="users")
     * @ORM\JoinColumn(name="division_id", referencedColumnName="id", onDelete="CASCADE")
     */
    private $division;
}

When the User is deleted, all Divisions will be deleted, but when one Division is deleted, the $users field will not be NULL because the User table will not even have a division field.
To check for emptiness, you will need to do something like this

$user->getUsers()->isEmpty()