Common app_label for all the models in Django

Question

I have many classes in models.py something like:

class SomeClass1(BaseModel):
    question = models.ForeignKey(Question)
    image = models.ForeignKey(Image)

class SomeClass2(BaseModel):
    question = models.ForeignKey(Question)
    option_text = models.TextField()

Now, I want to add app_label = 'my_app_label1' to all of these classes, something like this:

class SomeClass1(BaseModel):
    question = models.ForeignKey(Question)
    image = models.ForeignKey(Image)
    class Meta:
        app_label = 'my_app_label1'

But since there are many classes, so instead of adding app_label = 'my_app_label1' to all the classes, I'm adding app_label = 'my_app_label1' to the BaseModel, like this:

class BaseModel(models.Model):
    """
    For future abstraction.
    """
    class Meta:
        app_label = 'ques_app_data'

After which I'm getting this error:

myapp.SomeClass1.basemodel_ptr: (fields.E300) Field defines a relation with model 'BaseModel', which is either not installed, or is abstract.

Can anyone please explain how to solve this ?

Does the name of your app match the name you pass to app_label? — Igor Pejic, Jul 26 '15 at 15:11
Nope, it doesnt, but I want to give the same app_label for models across different apps — Saurabh Verma, Jul 26 '15 at 15:12
It has to be the same name it is included in settings, I think. Try that. — Igor Pejic, Jul 26 '15 at 15:12
I want to give the same app_label for models across different apps — Saurabh Verma, Jul 26 '15 at 15:13
Why would you want to do that? app_label is used when you have models in a place in which django doesn't know to which app they belong. — Igor Pejic, Jul 26 '15 at 15:16

Rahul Gupta · Answer 1 · 2015-07-27T04:47:02.330

3

Try specifying abstract=True in BaseModel inner Meta class.

class BaseModel(models.Model):
    """
    For future abstraction.
    """
    class Meta:
        abstract=True # specify this model as an Abstract Model
        app_label = 'ques_app_data'

Then inherit this BaseModel class in your model classes.

All the child model classes inherit the Meta class attributes of parent BaseModel class. Django will make one adjustment though to the Meta class of an abstract base class, before installing the Meta attribute in a child class, it sets abstract=False. This is done so that children of abstract base classes don’t automatically become abstract classes themselves.

After doing this, you will need to run the migrations again.

Note: There must be an app in your project by the name ques_app_data for this to work.

edited Jul 27 '15 at 04:47

answered Jul 26 '15 at 16:28

Rahul Gupta

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Yes, I did this, but after this makemigrations is not creating the tables for child classes – Saurabh Verma Jul 26 '15 at 16:29
What error are you getting? can you post the traceback – Rahul Gupta Jul 26 '15 at 16:34
No Error. Normal Execution (without extending BaseClass) Migrations for 'SomeClass1': 0003_usersubscription2.py: - Create model UserSubscription2 But while extending BaseClass, I get nothing – Saurabh Verma Jul 26 '15 at 16:36
Specifying a different name for `BaseModel` might help if migrations had been run without it being `abstract`. Check this link. http://stackoverflow.com/questions/7108899/using-django-south-to-move-from-concrete-inheritance-to-abstract-inheritance – Rahul Gupta Jul 26 '15 at 16:36
Name is not BaseModel, it's something else – Saurabh Verma Jul 26 '15 at 16:37
Try running all the migrations again using `migrate` command instead of `makemigrations`. Also check this similar link if it helps. http://stackoverflow.com/questions/5424262/django-permission-inheritance-problem-and-meta – Rahul Gupta Jul 26 '15 at 17:51
Also, there must be an app in your project by the name `ques_app_data` to work. – Rahul Gupta Jul 27 '15 at 04:45

score 1 · Accepted Answer · edited May 23 '17 at 11:52

1

This post answers this question: makemigrations not detecting changes for Extended Models in Django 1.7

having 2 major points:

1) We must have

class Meta:
        abstract = True

in BaseClass

2) app_label ques_app_data is must be included in INSTALLED_APPS

edited May 23 '17 at 11:52

Community

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answered Jul 27 '15 at 05:40

Saurabh Verma

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Common app_label for all the models in Django

2 Answers2