Django 通过多对多额外字段获取查询集

Question

我有两个类对象之间的多对多关系，我需要通过多对多额外字段过滤查询集

那是我的 3 类

class Card(models.Model):
    title = models.CharField(max_length=250 )
    tags = models.ManyToManyField(Tag, through='Cards_Tags')

class Tag(models.Model):
    tag = models.ForeignKey(Tag, on_delete=models.CASCADE)

class Cards_Tags(models.Model):
    tag = models.ForeignKey(Tag, on_delete=models.CASCADE)
    card = models.ForeignKey(Card, on_delete=models.CASCADE)
    field = models.CharField( max_length=25, blank=True )

如果我使用它，它会起作用，但它 returns 一个 Cards_Tags 的查询集，我需要与标签对象相同的结果

developers = Cards_Tags.objects.filter(card=obj, field='developer')

如何获取标签查询集，其中 Cards_Tags 中的 m2m 关系具有字段='developer'？

Answer 1

您可以过滤：

Tag.objects.filter(<strong>cards_tags__card=obj, cards_tags__field='developer'</strong>)

或者您可以完成 ManyToManyField:

obj<strong>.tags</strong>.filter(<strong>cards_tags__field='developer'</strong>)

Note: Models in Django are written in PascalCase, not snake_case, so you might want to rename the model from ~~Cards_Tags~~ to CardTag. In that case you filter with obj.tags.filter(cardtag__field='developer')

Django 通过多对多额外字段获取查询集

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