通過 model 獲取所有帶有過濾器的相關對象

Question

我有下一個數據庫結構：

class Artwork():
    id = models.IntegerField(_('id'), primary_key=True)
    artists = models.ManyToManyField('gql_service.Artist',
                                     through='gql_service.ArtistArtwork')

class ArtistArtwork(models.Model): 
    artist = models.ForeignKey('gql_service.Artist')
    artwork = models.ForeignKey('gql_service.Artwork')
    is_main_artist = models.BooleanField(default=False)

class Artist(models.Model):
    id = models.IntegerField(_('id'), primary_key=True)

is_main_artist特征標志用於定義該藝術家是否是該藝術品的主要藝術家。
在ArtworkNode我想定義main_artist字段：

class ArtworkNode(PrimaryKeyMixin, DjangoObjectType):
    main_artist = graphene.Field('escher.gql_service.schema.artist_node.ArtistNode')
    def resolve_main_artist(self, _):
        return ArtworkInfo(self).main_artist

然后在ArtworkService中，我可以訪問藝術品藝術家，例如：

class ArtworkInfo(object):
    @property
    def main_artist(self):
        artist = self.artwork.artists.first()

        return artist

有什么方法可以過濾ArtworkInfo上的藝術家並僅獲取一位主要藝術家或訪問ArtistArtwork model 中的值？

Answer 1

您可以使用相關名稱：

class ArtistArtwork(models.Model): 
    ...
    artwork = models.ForeignKey('gql_service.Artwork', related_name='artwork_artistartwork')

然后在ArtworkService

class ArtworkInfo(object):
    @property
    def main_artist(self):
        artist = self.artwork.objects.filter(artwork_artistartwork__is_main_artist=True).first()
        return artist

Answer 2

它是這樣的：

    @property
    def main_artist(self):
        return self.artwork.artists.filter(
            artistartwork__is_main_artist=True
        ).first()