python 如何在 Django 中使用动态外键？
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How to use dynamic foreignkey in Django?
提问by Anakin
I want to connect a single ForeignKeyto two different models.
我想将一个连接ForeignKey到两个不同的模型。
For example:
例如：
I have two models named Castsand Articles, and a third model, Faves, for favoriting either of the other models. How can I make the ForeignKeydynamic?
我有两个名为Castsand 的模型Articles，以及第三个模型Faves，用于偏爱其他模型中的任何一个。我怎样才能使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)
Is this possible?
这可能吗？
回答by vikingosegundo
Here is how I do it:
这是我如何做到的：
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)
You would add something like
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')
to Faves and
到最爱和
fields.GenericRelation(Faves)
to Article and Cast
文章和演员
回答by S.Lott
Here's an approach. (Note that the models are singular, Django automatically pluralizes for you.)
这是一个方法。（请注意，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)
This rarely presents profound problems. It may require some clever class methods, depending on your use cases.
这很少会带来深刻的问题。它可能需要一些巧妙的类方法，具体取决于您的用例。
