[Django]-How to make my models follow DRY principles

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2đź‘Ť

âś…

Using abstract base models:

class JobAd(models.Model):
    title = models.CharField(max_length=225)
    description = models.TextField()
    created_at = models.DateTimeField(auto_now=True)

    class Meta:
        abstract = True

class PostFirstJobAd(JobAd):
    pass

class PostSecondJobAd(JobAd):
    pass

class PostThirdJobAd(JobAd):
    pass

This would create 3 tables. The base class JobAd does not have a table in the db.

Since you appear to have 3 different models with the exact same code, you should question whether you really need 3 different models at all. Another option is to just store them all in one table, and add another field for the “other” thing. 

class JobAd(models.Model):
    pos = models.CharField(max_length=100, choices=['first', 'second', 'third'])
    title = models.CharField(max_length=225)
    description = models.TextField()
    created_at = models.DateTimeField(auto_now=True)

An integer field for pos is also possible.

👤wim

1đź‘Ť

First off, the abstract models might be what you need here. Depending on the business requirements, you may need to think a little harder on the architecture.

If, in fact, you do need to use abstract base classes:

class BaseJob(models.Model):
    title = models.CharField(max_length=255)
    # etc...

    class Meta:
        abstract = True

    def method_1(self):
        # base methods that work for instance data

Once that is defined, you can implement the base class in a concrete model. A concrete model is a model that doesn’t use the abstract = True metaclass property (or proxy, etc.) like so:

class Job(BaseJob):
    pass

If you need additional fields you can define them like any other model field but when you run makemigrations you’ll find the fields get added in the migration generated.

👤theWanderer4865

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