Question

我正在使用此方法来处理多对多关系的嵌套序列化中的更新。

def update(self, instance, validated_data):
    songs = validated_data.pop('suggested_songs')
    updated_instance = super(MessagesSerializer, self).update(instance, validated_data) 
    updated_instance.save()
    for song_data in songs:
        s = Song(**song_data)
        s.save()
        updated_instance.suggested_songs.add(s)

但是我注意到，在尝试更新数据时，会发生重复的歌曲，而不是编辑现有的歌曲。

我认为有一种方法可以在添加新的之前清除“suggested_songs”，但理想情况下我会正确编辑现有数据，我该如何实现？

修改

除非我指定ID，否则我的第二次尝试无效：

def update(self, instance, validated_data):
    suggested_songs_data = validated_data.pop('suggested_songs')
    updated_instance = super(MessagesSerializer, self).update(instance, validated_data)
    updated_instance.save()
    for song_data in suggested_songs_data:
        #songID = song_data.pop('id') # Grabbing the song ID so that we can check if the ID already exists. 
        #print(songID)
        s = Song(**song_data)
        print(song_data)
        print(instance)
        print("HELLO")
        print(suggested_songs_data)
    # If the song already exists we want to edit  
        print("+++ DEBUG ------------------------- DEBUG +++")
        s.id = '20'
        print(s.id)
        print(s.title)
        if Song.objects.filter(id = s.id).exists():
            print("FOUND OBJECT")
            # If the object exists, then we should edit it. 
            foundSong = Song.objects.get(id=s.id)
            print(foundSong.title)
        # We should be editing song. 
            foundSong.title = s.title
            foundSong.artist = s.artist
            foundSong.album = s.album
            foundSong.albumId = s.albumId
            foundSong.num_votes = s.num_votes
            foundSong.cleared = s.cleared
            foundSong.save()
        else:
            # no object satisfying query exists, so lets create a new one. 
            s.save()
            updated_instance.suggested_songs.add(s)
    return updated_instance

Django Rest Framework def更新是复制对象

0 个答案: