python-3.x - Peewee ManyToMany 关系的中间表上的额外字段

Question

我正在尝试通过 Peewee 3.2.2 中带有额外列的中间表建立多对多关系，如下所示:

ThroughDeferred = DeferredThroughModel()

class Playlist(BaseModel):
    ...
    movies = ManyToManyField(Movie, backref='playlists', through_model=ThroughDeferred)

class Movie(BaseModel):
    name = CharField(max_length=100)

class PlaylistMovie(BaseModel):
    playlist = ForeignKeyField(column_name='playlist_id', field='id', model=Playlist)
    movie = ForeignKeyField(column_name='movie_id', field='id', model=Movie)
    position = PositiveSmallIntegerField(default=1)

    class Meta:
        table_name = 'playlist_movie_relation'

ThroughDeferred.set_model(PlaylistMovie)

但是，在查询时我得到的只是没有位置的相关电影数据列表。

list(playlist.movies.dicts()) 
> [{name: 'blah', id: 3}, ...]

如何获取 playlist.movi​​es 中的位置数据？

Answer 1

这应该有效:

query = (Movie
         .select(Movie, PlaylistMovie.position)
         .join(PlaylistMovie)
         .where(PlaylistMovie.playlist == playlist)
         .order_by(PlaylistMovie.position))

for movie in query:
    print(movie.name, movie.playlistmovie.position)