from django.db import models
from django.utils.timezone import now

class BaseModel(models.Model):
    creation_date = models.DateTimeField(default=now, editable=False)
    last_update = models.DateTimeField(default=now)

    class Meta:
        abstract = True

    def get_parent_reference(self):
        """Override in child models to provide parent reference"""
        return None, None

class SideStoreModel(BaseModel):
    store_id = models.CharField(max_length=100)

    class Meta:
        abstract = True