嘿，我完全懂你现在的困扰！你用ForeignKey肯定不行，因为它只能建立一对多的关联——一个Track可以被多个Playlist引用，但一个Playlist只能绑定一个Track，这和你想要的“一个歌单多首歌、一首歌多个歌单”完全相反。

你需要的是Django的**ManyToManyField**，专门用来处理这种多对多的关联场景。下面是修改后的代码，我会标注关键改动：

from django.db import models
from django.contrib.auth.models import User
from .validators import *

# Model that actually contains user's tracks/songs
class Track(models.Model):
    title = models.CharField(max_length=40, null=True)
    description = models.CharField(max_length=500, null=True)
    author = models.ForeignKey(User, default=None, on_delete=models.CASCADE)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    miniature = models.ImageField(upload_to='images/track', default="defaults/default.png", validators=[validate_miniature_file_extension])
    audio_or_video = models.FileField(upload_to='audio_and_video/', default="file_not_found", validators=[validate_track_file_extension])

# Model that contains playlists
class Playlist(models.Model):
    title = models.CharField(max_length=40, null=True)
    description = models.CharField(max_length=500, null=True)
    author = models.ForeignKey(User, default=None, on_delete=models.CASCADE)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    miniature = models.ImageField(upload_to='images/playlist', default="defaults/default.png", validators=[validate_miniature_file_extension])
    # 关键改动：把ForeignKey换成ManyToManyField，字段名改成小写更符合Django规范
    tracks = models.ManyToManyField(Track, related_name='playlists')

几个重要说明： #

• related_name='playlists'：这个参数是为了反向查询更方便——以后你想获取某首歌所属的所有歌单时，可以直接用track.playlists.all()，而不是默认的track.playlist_set.all()，可读性更强。
• 如果不需要额外的关联信息（比如曲目在歌单里的排序、添加时间），这样就足够了，Django会自动创建中间表来维护两者的关联关系。
• 如果你需要在关联时存储额外数据（比如用户把这首歌加入歌单的时间），可以用through参数自定义中间表，比如：

  class PlaylistTrack(models.Model):
      playlist = models.ForeignKey(Playlist, on_delete=models.CASCADE)
      track = models.ForeignKey(Track, on_delete=models.CASCADE)
      added_at = models.DateTimeField(auto_now_add=True)
      position = models.IntegerField(default=0)
  
  # 然后在Playlist里修改：
  tracks = models.ManyToManyField(Track, through=PlaylistTrack, related_name='playlists')
  

简单使用示例： #

# 创建一个歌单和两首歌
playlist = Playlist.objects.create(title="我的最爱", author=request.user)
track1 = Track.objects.create(title="歌曲A", author=request.user)
track2 = Track.objects.create(title="歌曲B", author=request.user)

# 给歌单添加歌曲
playlist.tracks.add(track1, track2)

# 获取歌单里的所有歌曲
all_tracks_in_playlist = playlist.tracks.all()

# 获取某首歌所属的所有歌单
all_playlists_for_track = track1.playlists.all()

这样就能完美实现你想要的功能啦！

内容的提问来源于stack exchange，提问作者Dolidod Teethtard