CODEWITHSUNDEEP
pythondjangodjango-modelsforeign-keysdjango-queryset
Max Smith
Max Smith

Reputation: 945

How to get a related objects queryset through multiple levels of reverse foreignkeys in django?

I have a model of the sort:

class Publisher(models.Model):
    ...

class Author(models.Model):
    publisher = models.ForeignKey(Publisher, on_delete=models.CASCADE)

class Article(models.Model):
    author= models.ForeignKey(Author, on_delete=models.CASCADE)

Now I'm trying to get all the articles from a given publisher 'pub'. I've tried doing the following:

pub.article_set()

pub.authot_set().article_set()

As well as other failed tentatives. So how can I retrieve a Queryset of all articles of a given publisher without hitting the database too many times? Whats the most efficient way?

Thanks in advance!

Upvotes: 3

Views: 1723

Answers (1)

arjunattam
arjunattam

Reputation: 2819

The most efficient way to reduce number of database queries will be to filter on the queryset of Articles.

# pub is the instance of Publisher
articles = Article.objects.filter(author__publisher=pub)

Upvotes: 5

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