如何在Django中使用动态外键？

Question

我想连接一个ForeignKey到两个不同的模型.

例如:

我有一个名为两款车型Casts,并Articles和第三个模型,Faves为加入最爱无论是其他车型.我该如何制作ForeignKey动态？

class Articles(models.Model):
    title = models.CharField(max_length=100)
    body = models.TextField()

class Casts(models.Model):
    title = models.CharField(max_length=100)
    body = models.TextField()

class Faves(models.Model):
    post = models.ForeignKey(**---CASTS-OR-ARTICLES---**)
    user = models.ForeignKey(User,unique=True)

这可能吗？

Answer 1

我是这样做的:

from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes import fields


class Photo(models.Model):
    picture = models.ImageField(null=True, upload_to='./images/')
    caption = models.CharField(_("Optional caption"),max_length=100,null=True, blank=True)

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = fields.GenericForeignKey('content_type', 'object_id')

class Article(models.Model):
    ....
    images     = fields.GenericRelation(Photo)

你会添加类似的东西

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = fields.GenericForeignKey('content_type', 'object_id')

收藏和

    fields.GenericRelation(Faves)

文章和演员

contenttypes docs

Answer 2

这是一种方法.(注意,模型是单数,Django会自动为您复数.)

class Article(models.Model):
    title = models.CharField(max_length=100)
    body = models.TextField()

class Cast(models.Model):
    title = models.CharField(max_length=100)
    body = models.TextField()

FAVE_CHOICES = ( 
    ('A','Article'),
    ('C','Cast'),
)
class Fave(models.Model):
    type_of_fave = models.CharField( max_length=1, choices=FAVE_CHOICES )
    cast = models.ForeignKey(Casts,null=True)
    article= models.ForeigKey(Articles,null=True)
    user = models.ForeignKey(User,unique=True)

这很少会带来深刻的问题.它可能需要一些聪明的类方法,具体取决于您的用例.