Django模型主键成对 [英] Django model primary key as a pair

问题描述

我正在尝试开发一个应用程序，用户可以登录该应用程序并可以将歌曲添加到他们的收藏夹列表中。我正在为此定义M2M关系。

I am trying to make an app where users will login to their profile and can add songs to their favorite list. I am defining a M2M relationship for this.

我的问题是怎么说（歌曲，歌手）的组合是唯一的？我搜索了
，发现有可能通过unique_together。

My question is how to say combination of (song, singer) is unique? I searched and found that it may be possible through unique_together. Is this the correct way of setting this?

models.py：

models.py:

from django.contrib.auth.models import User


class Singer(models.Model):
    name = models.CharField(max_length=500, unique=True)

    def __str__(self):
       return self.name


class Song(models.Model):
   id = models.AutoField(primary_key=False)
   singer = models.ForeignKey(Singer, on_delete=models.CASCADE, related_name='song')
   name = models.CharField(max_length=500)

   Class Meta:
       unique_together = (singer, id)

   def __str__(self):
       return self.name

class Profile(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    songs = models.ManyToManyField(Song,  related_name='profile')

    def __str__(self):
        return self.user.username

请随时纠正我的模型.py，

Please feel free to correct my models.py, if you think the relationship is not correct.

谢谢，

推荐答案

我将使用默认的主键（自动字段），并使用元类属性unique_together

I would use a default primary key (auto field), and use the meta class property, unique_together

   class Song(models.Model):
       singer = models.ForeignKey(Singer, on_delete=models.CASCADE, related_name='song')
       name = models.CharField(max_length=500)

        class Meta:
            unique_together = (("singer", "name"),)

它将充当代理主键列。

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