Specify default value for a Model's RelatedFields related_name.

[renaud.parent@…]

It would be nice to be able to define a specific default "model-based" related_name value for RelatedField fields. Currently it is <model_name>_set, and can be overriden when defining one field.

E.g.

class Author(models.Model):
    # ...
    pass

  class Editor(models.Model):
    # ...
    pass

  class Book(models.Model):
    editor = models.ForeignKey(Editor, related_name="books")
    authors = models.ManyToManyField(Author, related_name="books")

It would be nice to be able to define the model Book in some way that would look like this :

class Book(models.Model):
    class Meta:
      default_related_name = "books"
    editor = models.ForeignKey(Editor)
    authors = models.ManyToManyField(Author)

See discussion at ​http://stackoverflow.com/questions/24062280/django-is-it-possible-to-define-a-class-related-name-for-all-relational-fields

[anonymous]

Would something like this be ok ?

​https://github.com/RenaudParent/django/commit/ea49025a4eefeb01fed27b118630b8991318a64f

[Aymeric Augustin]

This seems to be good idea. I'm surprised it didn't come up before. I searched Trac's achive of tickets without success.

[Renaud Parent]

I have started a working branch for this ticket, it is available here :

​https://github.com/RenaudParent/django/tree/ticket_22778

[Renaud Parent]

I have submitted a pull request at ​https://github.com/django/django/pull/2785
All tests pass under sqlite

[Tim Graham]

Comments for improvement on PR. Please uncheck "Patch needs improvement" when you update it, thanks.

[jorgecarleitao]

Hi RenaudParent, thanks for the patch.

I've reviewed your PR and made minor comments on the PR in github. It seems promising.

As far as I can tell, the PR still requires:

1. to address Meta subclassing: i.e. what happens when the Model is subclassed? At the moment it seems the default_related_name is inherited, which can cause a clash; see [1].

2. tests: it passes all tests means it is compatible with current Django functionality, which is great; however, we must ensure it is also compatible with what we want to achieve with it, namely, that if we add a default_related_name to Meta, the relations without related_name get the default one, while others don't. We may also want to test subclassing.

3. documentation: besides being in the API for Meta, it would be nice to document it in other places, specially in docs/db/models, section "Be careful with related_name".

(after 1.-3.)

4. There should be an item in docs/releases/1.X.rst (X=8?) describing this new functionality.

5. If core devs agree, refactor tests where this new functionality can be useful. For example, the model Book in tests/costum_managers/models.py seems a good candidate.

[1] ​https://docs.djangoproject.com/en/dev/topics/db/models/#be-careful-with-related-name

[Renaud Parent]

I have pushed a new commit based on previous comments here : ​https://github.com/RenaudParent/django/commit/8710030d4c52b1c542e735fdf026fdcd0842518a

[Tim Graham <timograham@…>]

In 5a3ae7e260f68602b25dbe3fc6ed13249a5c6515:

Created a new tests folder (model_options).

And moved tablespaces option tests to it.
The new folder can be used to test models/options, like the new option
added in refs #22778.

[Tim Graham <timograham@…>]

In 7bd2ad1dd9fc449ed1b4832fab5c975d7c8aa895:

[1.7.x] Created a new tests folder (model_options).

And moved tablespaces option tests to it.
The new folder can be used to test models/options, like the new option
added in refs #22778.

Backport of 5a3ae7e260 from master

[Renaud Parent]

Ok thanks, I just updated my commit.

[Renaud Parent]

I have pushed a new commit based on comments.

​https://github.com/RenaudParent/django/commit/3c1ed1ff97a306dc5b907551c09cdefe3258b3b3

[Tim Graham <timograham@…>]

In 87d0a3384cc263fe0df749a28e2fbc1e1240f043:

Fixed #22778 -- Added a model Meta option to define default_related_name.

Thanks jorgecarleitao and mmardini for reviews.