原则 2 OneToMany 级联 SET NULL

发布于 2024-12-27 02:31:46 字数 529 浏览 1 评论 0原文

错误

无法删除或更新父行：外键约束失败。

课程

class Teacher {

    /**
     *@ORM\OneToMany(targetEntity="publication", mappedBy="teacher")
     */
    protected $publications;
}

class Publication {

    /**
     * @ORM\ManyToOne(targetEntity="Teacher", inversedBy="publications")
     * @ORM\JoinColumn(name="teacher_id", referencedColumnName="id")
     */
    protected $teacher;
}

我想要的

我想要的是当你删除教师时，id_teacher 被修改为 NULL。我想保留该出版物，但不提及教授。

我不知道在教义中如何做到这一点，可能吗？或者总是与老师有关系？

原文

The error

Cannot delete or update a parent row: a foreign key constraint fails.

The classes

class Teacher {

    /**
     *@ORM\OneToMany(targetEntity="publication", mappedBy="teacher")
     */
    protected $publications;
}

class Publication {

    /**
     * @ORM\ManyToOne(targetEntity="Teacher", inversedBy="publications")
     * @ORM\JoinColumn(name="teacher_id", referencedColumnName="id")
     */
    protected $teacher;
}

I want

What I want is to make it that when you delete a teacher, the id_teacher is modified to NULL. I want to keep the publication but without reference to Professor.

I don't know how do that in Doctrine, Is it possible? Or always the relationship has to be with a teacher?

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那一片橙海， 2025-01-03 02:31:46

您应该在实体 Publication 的注释中添加选项 onDelete="SET NULL" ，如下所示：

class Publication
{
    /**
    * @ORM\ManyToOne(targetEntity="Teacher", inversedBy="publications")
    * @ORM\JoinColumn(name="teacher_id", referencedColumnName="id", onDelete="SET NULL")
    */
    protected $teacher;
}

此修改在表声明本身中注册。因此，您需要进行数据库迁移或架构更改才能使其生效。

You should add the option onDelete="SET NULL" in the annotation of your entity Publication like this:

class Publication
{
    /**
    * @ORM\ManyToOne(targetEntity="Teacher", inversedBy="publications")
    * @ORM\JoinColumn(name="teacher_id", referencedColumnName="id", onDelete="SET NULL")
    */
    protected $teacher;
}

This modification is registered in the table declaration itself. Hence, you need a database migration or a schema change for this to take effect.

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微暖i 2025-01-03 02:31:46

对于 Symfony 6 (PHP 8)（引擎“InnoDB”）

#[ORM\JoinColumn(nullable: true, onDelete: 'SET NULL')]

For Symfony 6 (PHP 8) (Engine 'InnoDB')

#[ORM\JoinColumn(nullable: true, onDelete: 'SET NULL')]

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三生殊途 2025-01-03 02:31:46

老问题，所以这适合任何寻找解决方案的人。

如果您不想对数据库架构进行任何更改，您可以使用学说事件系统：

use Doctrine\ORM\Mapping as ORM;

...

#[ORM\PreRemove]
public function clearPublications(): void
{
    foreach ($this->getPublications() as $publication) {
        $publication->setTeacher(null);
    }
}

Old question, so this is for anyone searching for solution.

In case you don't want to make any changes to database schema you can make use of doctrine event system:

use Doctrine\ORM\Mapping as ORM;

...

#[ORM\PreRemove]
public function clearPublications(): void
{
    foreach ($this->getPublications() as $publication) {
        $publication->setTeacher(null);
    }
}

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