How can I get the object count for a model in Django's templates?


Question

I'm my Django application I'm fetching all the objects for a particular model like so:

secs = Sections.objects.filter(order__gt = 5)

I pass this varbiles to my templates and i can access all the properties of the Model like section.name, section.id, etc.

There is a model called Books which has a FK to the Sections model. When i iterate over the secs varible in my template, how can i access the count of Books for each Section? Something like {{ sec.Books.count }}??

Thank you

1
34
2/18/2015 4:00:11 PM

Accepted Answer

If Books has a ForeignKey to Sections, then Django will automatically create a reverse relationship from Sections back to Books, which will be called books_set. This is a Manager, which means you can use .filter(), .get() and .count() on it - and you can use these in your template.

{{ sec.books_set.count }}

(By the way, you should use singular nouns for your model names, not plurals - Book instead of Books. An instance of that model holds information for one book, not many.)

71
8/3/2010 11:39:52 AM

Additionally to what Daniel said, Django creates reverse relationships automatically (as Daniel said above) unless you override their names with the related_name argument. In your particular case, you would have something like:

class Book(models.Model):
    section = models.ForeignKey(Section, related_name="books")

Then you can access the section's books count in the template by:

{{ sec.books.count }}

As you intimated in your question.


Licensed under: CC-BY-SA with attribution
Not affiliated with: Stack Overflow
Icon