如何在 Django 模型中声明一个 class 并且属性指向相同的 class？

Question

如何声明指向相同 class 类型的上一个或下一个属性？

中找不到答案

在下面的 models.py 中，我刚刚为 previous 和 next

写了“场景”

from pickle import TRUE
from django.db import models
from django.contrib.auth.models import User

class scenes(models.Model):
    name = models.CharField('Event name', max_length=120)
    record_date = models.DateTimeField('Event date')
    manager = models.ForeignKey(User, blank=True, null=True, on_delete=models.SET_NULL)
    description = models.TextField(blank=True)
    previous = models.ForeignKey(scenes, blank=True, null=True, on_delete=models.SET_NULL)
    next = models.ForeignKey(scenes, blank=True, null=True, on_delete=models.SET_NULL)

    def __str__(self):
        return self.name

Answer 1

您可以使用'self'来引用相同的模型。但在这里您可能可以使用 OneToOneField ^[Django-doc] with next as value for the related_name=… parameter ^[Django-doc] 作为 previous 字段。这样，当您将 B 设置为 A 的 next 时，A 就是 previous 的 B 自动：

from pickle import TRUE
from django.db import models
from django.conf import settings

class scenes(models.Model):
    name = models.CharField('Event name', max_length=120)
    record_date = models.DateTimeField('Event date')
    manager = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        blank=True,
        null=True,
        on_delete=models.SET_NULL
    )
    description = models.TextField(blank=True)
    previous = models.<strong>OneToOneField(</strong>
        <strong>'self'</strong>,
        blank=True,
        null=True,
        <strong>related_name='next'</strong>
        on_delete=models.SET_NULL
    )

    def __str__(self):
        return self.name

Note: It is normally better to make use of the settings.AUTH_USER_MODEL ^[Django-doc] to refer to the user model, than to use the User model ^[Django-doc] directly. For more information you can see the referencing the User model section of the documentation.

如何在 Django 模型中声明一个 class 并且属性指向相同的 class？

How to declare in Django Models a class with an attribute pointing to the same class?

django

django-models