CODEWITHSUNDEEP
databasedjangodjango-modelsrelational-databaseforeign-key-relationship
goelv
goelv

Reputation: 2884

How do I hard-code a type into my models in Django

Here's the logic for the models:

  1. Category. There are several categories; each category can contain several products.
  2. Product. There are several products; each product can only have one category.

Is it possible to specify what kind of category each product is within the model file itself? For example: can I set the model so that a shirt can only be clothing and nothing else?

Here's what I have so far (it doesn't validate):

class Category(models.Model):
   CATEGORY_CHOICES = (
        ('CLOTHING', 'Clothing'),
        ('FURNITURE', 'Furniture'),
   )
   category = models.CharField(choices=CATEGORY_CHOICES)


class Shirt(Product):
    category = models.ForeignKey(Category, default=CATEGORY_CHOICES.CLOTHING)

    class Table(Product):
       category = models.ForeignKey(Category, default=CATEGORY_CHOICES.FURNITURE)

I'm new at this. Thanks for the help!

Upvotes: 0

Views: 157

Answers (3)

Dmitry Shevchenko
Dmitry Shevchenko

Reputation: 32424

I suggest that you invest some time into adopting recently added model validation, while it's not automatic as forms validation (you'll have to call clean* methods yourself, probably inside save), you gonna get DRY validation that could be used on Model and Form level.

Upvotes: 1

Lycha
Lycha

Reputation: 10177

You can use callables to give instance as a default value

Something like this (untested code):

class Shirt(Product):

  def getClothingInstance():
    return Category.objects.get(category=Category.CATEGORY_CHOISES['CLOTHING'])

  category = models.ForeignKey(Category, default=getClothingInstance)

Upvotes: 0

Erik
Erik

Reputation: 7741

You can validate your model on save with any arbitrary rules. So, write a validation rule that checks that all shirts are saved in the category clothing.

For user input, create a form that only provides choices corresponding to the product.

Good luck!

Upvotes: 1

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