CODEWITHSUNDEEP
django-rest-framework
Empusas
Empusas

Reputation: 412

DRF common models and foreign key

I am trying to use some common attributes for all my objects in the DB like created_by, updated_by, created_when and updated_when.

So I created a class for the common attributes:

class CommonModel(models.Model):
"""Common fields that are shared among all models."""

    created_by = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT,
                               editable=False, related_name="+")
    updated_by = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT,
                               editable=False, related_name="+")
    created_at = models.DateTimeField(auto_now_add=True,
                                  editable=False)
    updated_at = models.DateTimeField(auto_now=True,
                                  editable=False)

Then I refer to the common model in my models:

class Tag(CommonModel):
"""Tag to be used for products"""
name = models.CharField(max_length=255)

    def __str__(self):
        return self.name


class Vendor(CommonModel):
    """Vendor to be used for products"""
    name = models.CharField(max_length=255, unique=True)

    def __str__(self):
        return self.name

But when I refer to the tag or vendors in another model as foreign_key then I get an error while executing the migration.

class Product(CommonModel):
"""Model for the type of a product"""
    product_id = models.CharField(max_length=255, unique=False)
    description = models.CharField(max_length=255, unique=False, null=True, blank=True, default='')
    vendor = models.ForeignKey(Vendor, blank=False, null=False, on_delete=models.SET_DEFAULT)
    tag = models.ForeignKey(Tag, null=True, blank=True, on_delete=models.SET_NULL)

Error message:

SystemCheckError: System check identified some issues:

ERRORS:

core.Product.tag: (models.E006) The field 'tag' clashes with the field 'tag' from >model 'core.commonmodel'.
core.Product.vendor: (models.E006) The field 'vendor' clashes with the field 'vendor' from model 'core.commonmodel'.

It was working fine before I introduced the common models.

Upvotes: 1

Views: 60

Answers (1)

Uzzal H. Mohammad
Uzzal H. Mohammad

Reputation: 811

You need to set abstract in Meta, after that it should work fine.

class CommonModel(models.Model):
"""Common fields that are shared among all models."""

    created_by = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT,
                               editable=False, related_name="+")
    updated_by = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT,
                               editable=False, related_name="+")
    created_at = models.DateTimeField(auto_now_add=True,
                                  editable=False)
    updated_at = models.DateTimeField(auto_now=True,
                                  editable=False)

    class Meta:
        abstract = True

Upvotes: 2

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