Django - 通过 related_query_name 获取对象

Question

I have the following Model at my models.py to store genre information for specific objects at my Database like Movies for example:

class Genre(models.Model):
    objects = RandomManager()
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    content_type = models.ForeignKey(ContentType, limit_choices_to=referential_genre_models, on_delete=models.CASCADE, verbose_name=_("Content Type"))
    object_id = models.CharField(max_length=36, verbose_name=_("Object ID"))
    content_object = GenericForeignKey('content_type', 'object_id')
    name = models.CharField(verbose_name=_("Genre"), blank=True, null=True, editable=False, max_length=50)
    date_added = models.DateTimeField(auto_now_add=True, verbose_name=_("Date Added"))

At my Movies model class I have the following field to connect the two models with each other:

genre_relation = GenericRelation(Genre, related_query_name='genre_relation')

At my views.py I now want to query onto specific Movies of genre "Comendy" and "Family" for example, but I don't get back any results:

movie_genre_assets = Movies.objects.get_queryset().filter(Q(genre_relation__name="Comedy") | Q(genre_relation__name="Family")).order_by('release_date')

Can smb.help?

Answer 1

Rather than a GenericRelation you should use a through table . This is a separate model with a foreign key to both Movie and Genre and each record forms a relation.

class Movie(models.Model):
    genre = models.ManyToManyField(through="MovieGenre")
    ...

class Genre(models.Model):
    ...

class MovieGenre(models.Model):
    movie = models.ForeignKey(Movie, on_delete=models.CASCADE)
    genre = models.ForeignKey(Genre, on_delete=models.CASCADE)

You can then access the movies belonging to a genre with:

movie.genre.all()

And all the genres belonging to a move with:

genre.movie_set.all()