CODEWITHSUNDEEP
pythondjangoinheritance
denvaar
denvaar

Reputation: 2214

Model Inheritance with Django

I have a class like this:

class ControlVocabulary(models.Model):
    definition = models.TextField()
    term = models.CharField(primary_key=True, max_length=255)

    class Meta:
        abstract = True

Why can't I use 'definition' inside of a child class? Is there a way that I can do this?

class ActionType(ControlVocabulary):
    definition = ControlVocabulary.definition # <-- Error
    class Meta:
        #...

UPDATE: It looks like this is not permitted in Django, but I am still searching for a work-around to this problem. In Django - Model Inheritance - Does it allow you to override a parent model's attribute?

My view class:

class VocabulariesView(ListView):
queryset = []
template_name = 'cvinterface/index.html'

def get_context_data(self, **kwargs):
    context = super(VocabulariesView, self).get_context_data(**kwargs)
    context['vocabulary_views'] = [{'name': vocabularies[vocabulary_name]['name'], 'definition': vocabularies[vocabulary_name]['definition'], 'url': reverse(vocabulary_name)}
                                   for vocabulary_name in vocabularies]

    return context

Part of vocabularies dictionary:

vocabularies = {
# optional keys:
# list_view, detail_view, list_template, detail_template

'actiontype': {
    'name': ActionType._meta.verbose_name,
    'definition': ActionType._meta.definition,
    'model': ActionType,
    'detail_template': 'cvinterface/vocabularies/actiontype_detail.html',
},

Upvotes: 0

Views: 172

Answers (1)

Abhishek
Abhishek

Reputation: 3068

You do not have to define the definition in your ActionType because it will be inherited already from your ControlVocabulary

You can check it already as follows:

x = ActionType.objects.all()
x[0].__dict__

Other way to check is by looking at the fields of you model in the database

EDIT:

Tried replicating the error:

models:

class ControlVocabulary(models.Model):
    definition = models.TextField()
    term = models.CharField(primary_key=True, max_length=255)
    class Meta:
        abstract = True
class ActionType(ControlVocabulary):
    #definition = ControlVocabulary.definition # <-- Error
    class Meta:
        verbose_name='Action'

and in the shell:

Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from testapp.models import *
>>> x = ActionType.objects.all()
>>> x
[]
>>> y = ActionType(definition='my definition')
>>> y.save()
>>> ActionType.objects.all()
[<ActionType: ActionType object>]

Upvotes: 1

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