属性错误：“ManyRelatedManager”对象没有属性“add”？我确实喜欢 django 网站，但遇到了这个错误

Question

for item in data:
    category_id = item['category_id']
    del item['category_id']

    category = Category.objects.get(pk=category_id)

    code = item['code']

    try:
        article = Article.objects.get(pk=code)
    except:
        article = Article(**item)
        article.save()

    # at this point I have the article & category, but the next
    # statement throws me an error:
    category.articles.add(article)
    category.save()

错误是：

   AttributeError: 'ManyRelatedManager' object has no attribute 'add'

Answer 1

JamesO 是正确的 - 看起来您的 Category.articles 字段具有直通关系。假设您的模型至少类似于以下内容

class Article(models.Model):
    name = models.CharField(max_length=128)

class Category(models.Model):
    name = models.CharField(max_length=128)
    articles = models.ManyToManyField(Article, through='Membership')

class Membership(models.Model):
    article = models.ForeignKey(Article)
    category = models.ForeignKey(Category)
    author = models.CharField()

，然后将文章添加到类别，您必须

m = Membership(article=article, category=category, author="Dan TM")
m.save()

注意 - 我们无法判断< code>through 字段被调用，因此 Membership 是一个猜测，受到 django 文档