Django:如何在类中添加模型类或引用? [英] Django: How to add model class inside class or refer?

问题描述

我有一个叫做Artist的类，它是一个艺术家的个人资料

I have a class called artist which is a profil for an artist

class Artist_object(models.Model):
    surname = models.CharField(max_length=120)
    name = models.CharField(max_length=120)
    Biography = models.TextField(default='Bitte Biography eingfügen', null=False)

现在，我希望这位艺术家可以创作多幅带有破坏性的画作.

now I want that this artist can have multiple paintings with a desrciption.

class Artist_painting(models.Model):
    painting1 = models.ImageField()
    painting1_desc = models.CharField(max_length=120, default=None)
    painting2 = models.ImageField()
    painting2_desc = models.CharField(max_length=120, default=None)

如何将类Artist_painting放到我查看的每个艺术家的Artist_object中(我得到了
def get_absolute_url(self):返回f'/artist/{self.id}')上有每张图片的描述?

How can I put class Artist_painting inside the Artist_object that for every artist I view (i got
def get_absolute_url(self): return f'/artist/{self.id}' ) it have an description for every image ?

推荐答案

这是一个关系， ManyToOne ，每个 Artist 有很多 Painting >， ManyToOne 关系称为 ForiegnKey ，因为 Artist 本身是 Painting 的键，每个绘画只有一名 Artist .

This is a relation, ManyToOne, Many Paintings for each Artist, ManyToOne relation is called ForiegnKey because the Artist himself is a key to the Painting, Each Painting has only one Artist.

class Artist(models.Model): 
    """
    no need to call it Artist_object, Stick with pep8 (ArtistObject)
    or better yet, Artist only because it's an object anyways.
    """
    surname = models.CharField(max_length=120)
    name = models.CharField(max_length=120)
    Biography = models.TextField(default='Bitte Biography eingfügen', null=False)

class Painting(models.Model):
   """
    Same naming rules apply
   """
   artist = models.ForiegnKey(Artist, on_delete=models.CASCASE, related_name="paintings")

• 相关名称是什么?

  • What's the related name?

    artist 是一个类变量，通过使用 painting_instance.artist 从 Painting 实例调用 artist 变量>，如果我们想获取与艺术家相关的 Painting ，那是通过使用 artist_instance.related_name ，在这种情况下是 artist_instance.paintings ，如果您未指定 related_name ，则默认为 painting_qs ，如果您不想访问反向关系，我的意思是 .paintings ，请使用 related_name ="+"

    artist is a class variable, Calling the artist variable from a Painting instance is by using painting_instance.artist, What if we wanted to get the Paintings associated with an artist, It's by using artist_instance.related_name and in this case, It's artist_instance.paintings, If you didn't specify a related_name, It will be painting_qs by default, If you don't want to have access to the reverse relation, I mean the .paintings, Use related_name="+"

    什么是 CASCASE ?

    这是一个基本的SQL短语，这意味着当 Artist 被删除时，也要删除其 Painting s.

    It's a basic SQL phrase which means, when the Artist gets deleted, delete his Paintings too.

    请参考此答案获取有关 ForiegnKey

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