Database modeling for products and store

Question

I am planning to develop a virtual shopping mall where stores of any kind can be registered, such as in a physical shopping mall. First I want to develop an efficient and effective database modeling for products and stores only. I wanted it be very flexible and user friendly. Here is the model design for Product and Store. How can I improve the database design?

My concern is mainly for the categories be user friendly. For example Men -> Clothing -> Shirts as a category. If you wish, you can help me to improve the design as well, I would appreciate all recommendations.

I am using Python 3 and Django 1.11.

DAY = (( 'Sun', 'Sunday'),
 ( 'Mon', 'Monday'),
 ( 'Tue', 'Tuesday'),
 ( 'Wed', 'Wednesday'),
 ( 'Thu', 'Thursday'),
 ( 'Fri', 'Friday'),
 ( 'Sat', 'Saturday')
 )
class OpeningHours(models.Model):
 store = models.ForeignKey('Store', related_name="opening_hour")
 weekday = models.CharField(choices=DAY, max_length=12)
 opening_hour = models.TimeField()
 closing_hour = models.TimeField()
 class Meta:
 verbose_name = 'Opening Hour'
 verbose_name_plural = 'Opening Hours'
 def ___str__(self):
 return '{} {} - {}'.format(self.weekday, str(self.opening_hour), str(self.closing_hour))
class Store(models.Model):
 merchant = models.ForeignKey(User, blank=True, null=False)
 token = models.CharField(default=token_generator, max_length=20, unique=True, editable=False)
 name_of_legal_entity = models.CharField(max_length=250, blank=False, null=False)
 pan_number = models.CharField(max_length=20, blank=False, null=False)
 registered_office_address = models.CharField(max_length=200)
 name_of_store = models.CharField(max_length=100)
 email = models.EmailField(blank=False, null=False)
 store_contact_number = models.PositiveIntegerField(blank=False, null=False)
 # store_long = models.DecimalField(max_digits=12, decimal_places=8, null=True)
 # store_lat = models.DecimalField(max_digits=12, decimal_places=8, null=True)
 is_active = models.BooleanField(default=True)
 class Meta:
 verbose_name = 'Store'
 def __str__(self):
 return self.name_of_store
 class Meta:
 verbose_name = 'Store'
 verbose_name_plural = 'Stores'
class Product(models.Model):
 store = models.ForeignKey(Store)
 token = models.CharField(default=token_generator, max_length=20, unique=True, editable=False)
 category = models.ForeignKey('CatalogCategory', related_name='products')
 brand = models.ForeignKey('Brand', related_name="product_brand")
 image = models.ImageField(upload_to='products/images/')
 name_of_product = models.CharField(max_length=120, blank=False,null=False)
 description = models.TextField(blank=False,null=False)
 price = models.DecimalField(decimal_places=2, max_digits=20)
 discount = models.DecimalField(decimal_places=2, max_digits=20)
 sales_price = models.DecimalField(decimal_places=2, max_digits=20)
 is_active = models.BooleanField(default=True)
 is_gurantee_available = models.BooleanField(default=False)
 is_negotiated = models.BooleanField(default=False)
 is_verified = models.BooleanField(default=False)
 is_instock = models.BooleanField(default=False)
 def __str__(self):
 return self.name_of_product
 class Meta:
 verbose_name = 'Product'
 verbose_name_plural = 'Products'
class Brand(models.Model):
 name = models.CharField(max_length=100, blank=True, null=True)
 logo = models.ImageField(upload_to='products/brand/images/')
 class Meta:
 verbose_name = 'Brand'
 verbose_name_plural = 'Brands'
 def __str__(self):
 return self.name
class Variation(models.Model):
 VAR_CATEGORIES = (
 ('size', 'size'),
 ('color', 'color'),
 )
 product = models.ForeignKey(Product)
 token = models.CharField(default=token_generator, max_length=20, unique=True, editable=False)
 category = models.CharField(max_length=10, choices=VAR_CATEGORIES)
 title = models.CharField(max_length=50)
 price = models.DecimalField(decimal_places=2, max_digits=20)
 discount = models.DecimalField(blank=True ,null =True, decimal_places=2, max_digits=20)
 active = models.BooleanField(default=True)
 quantity = models.IntegerField(null=True , blank=True)
 sales_price = models.DecimalField(blank=True ,null =True, decimal_places=2, max_digits=20)
 image = models.ImageField(upload_to='products/images/')
 class Meta:
 verbose_name = 'Variation'
 verbose_name_plural = 'Variations'
 def __str__(self):
 return '{0} of {1} from {2}' .format(self.product.name_of_product, self.title, self.product.store.name_of_store)
class CatalogCategory(models.Model):
 token = models.CharField(default=token_generator, max_length=20, unique=True, editable=False)
 parent = models.ForeignKey('self', blank=True, null=True, related_name='children')
 name = models.CharField(max_length=300)
 description = models.TextField(blank=True)
 class Meta:
 verbose_name = 'CatalogCategory'
 verbose_name_plural = 'CatalogCategories'
 def __str__(self):
 return self.name
class ProductImage(models.Model):
 product = models.ForeignKey(Product, null=True, blank=True, related_name="product_image")
 image = models.ImageField(upload_to='products/images/')
 updated = models.DateTimeField(auto_now_add=False, auto_now=True)
 @property
 def imageName(self):
 return str(os.path.basename(self.image.name))
 def __str__(self):
 return str(self.image)
 class Meta:
 verbose_name = 'Product Image'
 verbose_name_plural = 'Product Images'
class StoreCategory(models.Model):
 STORE_CATEGORIES= (
 ('GROCERY', ('Grocery')),
 ('MEATS', ('Meats')),
 ('FOODS & BEVERAGES', ('Foods')),
 ('COMPUTERS', ('Computers')),
 ('ELECTRONICS', ('Electronics')),
 ('HOME & OUTDOOR', ('Home & Outdoor')),
 ('FASHION & BEAUTY', ('Fashion & Beauty')),
 ('HEALTH', ('Health')),
 ('SPORTS & FITNESS', ('Sports & Fitness')),
 ('BABY', ('Baby')),
 ('BOOKS', ('Books')),
 )
 product = models.ForeignKey(Product,null=True, on_delete=models.CASCADE)
 store_category = models.CharField(choices=STORE_CATEGORIES, default='GROCERY', max_length=30)
 # objects = VariationManager()
 class Meta:
 verbose_name = 'Store Category'
 verbose_name_plural = 'Store Categories'
 def __str__(self):
 # return str(self.product.name_of_product)
 return '{0} of category {1}' .format(self.product.name_of_product, str(self.store_category))

Answer 1

The models look about right.

def imageName(self):

Well, ok, PEP-8 asks that you spell this image_name, but, whatever, I'm sure you had other constraints you were working within.

In STORE_CATEGORIES I don't understand why Foods is special. It otherwise has DRY issues that could be addressed by applying .upper() or .title() to a single copy of the list.

Looks good to me. Ship it!