CODEWITHSUNDEEP
pythondjangodjango-models
dm03514
dm03514

Reputation: 55972

Override Class Attribute, with a generic way to refer to class

I have a Django abstract Model.

class Company(models.Model):
   DEFAULT_EMPLOYEES = None
   employees = models.PositiveIntegerField(null=True, blank=True, 
                                           default=<<<what_goes_here>>>.DEFAULT_EMPLOYEES)
   class Meta:
       abstract = True

class BestBuy(Company):
   DEFAULT_EMPLOYEES = 1000

I am interested in overriding a class attribute to use as a default value. I was wondering if there was a generic way to refer to the class to make this possible. In Company I realize I can refer to attribute using Company.DEFAULT_EMPLOYEES, but is there a way like: "CurrentCLass".DEFAULT_EMPLOYEES.

I'm pretty sure self cannot work here, because there are no instances in these definitions. Just the classes

Is there a better way to approach this to allow children classes to specify a default value? Any help would be greatly appreciated. Thank you.

Upvotes: 1

Views: 204

Answers (2)

professorDante
professorDante

Reputation: 2405

Define a classmethod on your parent:

@classmethod
def showDefaultEmployees(cls):
    return cls.DEFAULT_EMPLOYEES

Then just call it from your class instance

BestBuy.showDefaultEmployees()

Upvotes: 0

Samuel Colvin
Samuel Colvin

Reputation: 13349

Best approach would be to replace the save function to set employees if it's blank at the time of saving.

Something like:

class Company(models.Model):
    ...
    def save(self, *args, **kw):
       if self.employees is None:
            self.employees = self.DEFAULT_EMPLOYEES
       super(Company, self).save(*args, **kw)

the define DEFAULT_EMPLOYEES in each child class as you have done.

The alternative is modifying the metaclass which is probably overkill.

Upvotes: 2

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