Sorry if this is too trivial but I have looked through the docs and
could not find a clear answer.
Given that I have a Book model with a ManyToManyField called authors
how do I get all the books for a particular author? Each book may have
more than one author, so I cannot filter the books using the standard
methods.
My models are:
class Author(models.Model):
name = models.CharField(max_length=124)
class Book(models.Model):
title = models.CharField(max_length=124)
authors = models.ManyToManyField(Author)
If I got it right, according to the documentation to get to a 'child'
queryset I have to iterate with 'for each b in Book.objects.all()',
and then call the b.authors.all() on each instance in order to check
if a particular author.id is found in the authors queryset. But how do
I get the results as a queryset? I could not get this to work.
To get all the books for a given author.id, I have tried:
def books_by_author(request, object_id):
'''does not work'''
filtered_by_author = []
for b in Book.objects.all():
if object_id in [a.id for a in b.authors.all()]:
filtered_by_author.append(b)
return render_to_response('polls/book_list.html', {'object_list':
filtered_by_author,} )
But this, of course, does not work, because it returns a list and not
a query set. What would be a proper, nice solution?
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