CODEWITHSUNDEEP
pythondjangodjango-modelsdjango-managers
Mariusz Jamro
Mariusz Jamro

Reputation: 31653

How to programatically get manager instance for model in Django

I have a custom manager added to model like that:

class StandardManagerModel(models.Model):
    pass

class PublishableManager(models.Manager):
    pass

class Publishable(models.Model):
    published_objects = PublishableManager()

This removes the default .objects manager from the model. How can i retrieve a default manager declared in model class? I would like a function like get_default_manager():

manager = get_default_manager(Publishable)
assert manager is Publishable.published_objects

manager = get_default_manager(StandardManagerModel)
assert manager is StandardManagerModel.objects

Upvotes: 2

Views: 3355

Answers (2)

radicalbiscuit
radicalbiscuit

Reputation: 487

Looks like you don't need a function at all. It's stored as an attribute on the model:

Model._default_manager

There's also Model._base_manager, which I can only assume is what the default manager would be if you don't provide one.

Upvotes: 5

Sayse
Sayse

Reputation: 43300

From the docs

If you use custom Manager objects, take note that the first Manager Django encounters (in the order in which they’re defined in the model) has a special status. Django interprets the first Manager defined in a class as the “default” Manager, and several parts of Django (including dumpdata) will use that Manager exclusively for that model. As a result, it’s a good idea to be careful in your choice of default manager in order to avoid a situation where overriding get_queryset() results in an inability to retrieve objects you’d like to work with.

You can supply the default manager as well

objects = models.Manager()
published_objects = PublishableManager()

Upvotes: 0

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