Reputation: 13206
I have the following 4 models in my program - User, Brand, Agency and Creator.
User is a superset of Brand, Agency and Creator.
A user can be a brand, agency or creator. They cannot take on more than one role. Their role is defined by the accountType
property. If they are unset (i.e. 0) then no formal connection exists.
How do I express this in my model?
User model
class User(models.Model):
id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
email = models.EmailField(max_length=255, null=True, default=None)
password = models.CharField(max_length=255, null=True, default=None)
ACCOUNT_CHOICE_UNSET = 0
ACCOUNT_CHOICE_BRAND = 1
ACCOUNT_CHOICE_CREATOR = 2
ACCOUNT_CHOICE_AGENCY = 3
ACCOUNT_CHOICES = (
(ACCOUNT_CHOICE_UNSET, 'Unset'),
(ACCOUNT_CHOICE_BRAND, 'Brand'),
(ACCOUNT_CHOICE_CREATOR, 'Creator'),
(ACCOUNT_CHOICE_AGENCY, 'Agency'),
)
account_id = models.ForeignKey(Brand)
account_type = models.IntegerField(choices=ACCOUNT_CHOICES, default=ACCOUNT_CHOICE_UNSET)
class Meta:
verbose_name_plural = "Users"
def __str__(self):
return "%s" % self.email
Brand model
class Brand(models.Model):
id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
name = models.CharField(max_length=255, null=True, default=None)
brand = models.CharField(max_length=255, null=True, default=None)
email = models.EmailField(max_length=255, null=True, default=None)
phone = models.CharField(max_length=255, null=True, default=None)
website = models.CharField(max_length=255, null=True, default=None)
class Meta:
verbose_name_plural = "Brands"
def __str__(self):
return "%s" % self.brand
Creator model
class Creator(models.Model):
id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
first_name = models.CharField(max_length=255, null=True, default=None)
last_name = models.CharField(max_length=255, null=True, default=None)
email = models.EmailField(max_length=255, null=True, default=None)
youtube_channel_username = models.CharField(max_length=255, null=True, default=None)
youtube_channel_url = models.CharField(max_length=255, null=True, default=None)
youtube_channel_title = models.CharField(max_length=255, null=True, default=None)
youtube_channel_description = models.CharField(max_length=255, null=True, default=None)
photo = models.CharField(max_length=255, null=True, default=None)
youtube_channel_start_date = models.CharField(max_length=255, null=True, default=None)
keywords = models.CharField(max_length=255, null=True, default=None)
no_of_subscribers = models.IntegerField(default=0)
no_of_videos = models.IntegerField(default=0)
no_of_views = models.IntegerField(default=0)
no_of_likes = models.IntegerField(default=0)
no_of_dislikes = models.IntegerField(default=0)
location = models.CharField(max_length=255, null=True, default=None)
avg_views = models.IntegerField(default=0)
GENDER_CHOICE_UNSET = 0
GENDER_CHOICE_MALE = 1
GENDER_CHOICE_FEMALE = 2
GENDER_CHOICES = (
(GENDER_CHOICE_UNSET, 'Unset'),
(GENDER_CHOICE_MALE, 'Male'),
(GENDER_CHOICE_FEMALE, 'Female'),
)
gender = models.IntegerField(choices=GENDER_CHOICES, default=GENDER_CHOICE_UNSET)
class Meta:
verbose_name_plural = "Creators"
def __str__(self):
return "%s %s" % (self.first_name,self.last_name)
Agency model
class Agency(models.Model):
id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
name = models.CharField(max_length=255, null=True, default=None)
agency = models.CharField(max_length=255, null=True, default=None)
email = models.EmailField(max_length=255, null=True, default=None)
phone = models.CharField(max_length=255, null=True, default=None)
website = models.CharField(max_length=255, null=True, default=None)
class Meta:
verbose_name_plural = "Agencies"
def __str__(self):
return "%s" % self.agency
Update:
So I've whittled it down to this bit here in the model:
ACCOUNT_CHOICE_UNSET = 0
ACCOUNT_CHOICE_BRAND = 1
ACCOUNT_CHOICE_CREATOR = 2
ACCOUNT_CHOICE_AGENCY = 3
ACCOUNT_CHOICES = (
(ACCOUNT_CHOICE_UNSET, 'Unset'),
(ACCOUNT_CHOICE_BRAND, 'Brand'),
(ACCOUNT_CHOICE_CREATOR, 'Creator'),
(ACCOUNT_CHOICE_AGENCY, 'Agency'),
)
account_type = models.IntegerField(choices=ACCOUNT_CHOICES, default=ACCOUNT_CHOICE_UNSET)
limit = models.Q(app_label='api', model='Brand') | \
models.Q(app_label='api', model='Creator') | \
models.Q(app_label='api', model='Agency')
content_type = models.ForeignKey(ContentType, limit_choices_to=get_content_type_choices(), related_name='user_content_type')
content_object = GenericForeignKey('content_type', 'email')
How do I accomplish this? Getting this error:
File "/Users/projects/adsoma-api/api/models.py", line 7, in <module>
class User(models.Model):
File "/Users/projects/adsoma-api/api/models.py", line 28, in User
content_type = models.ForeignKey(ContentType, limit_choices_to=get_content_type_choices(), related_name='user_content_type')
NameError: name 'get_content_type_choices' is not defined
Upvotes: 6
Views: 5236
Reputation: 413
Here is how I solve it, override the save
method check your condition
tested on Django 3.2
CUSTOMER = [
('customer', 'customer'),
('supplier', 'supplier'),
]
class Customer(models.Model):
name = models.CharField(max_length=256, null=False, blank=False)
user_type = models.CharField(max_length=32, choices=CUSTOMER)
class SupplierOrder(models.Model):
price = models.FloatField(default=0)
supplier = models.ForeignKey(Customer, related_name='supplier', on_delete=models.CASCADE)
def save(self, *args, **kwargs):
supplier = get_object_or_404(Customer, id=self.supplier.id)
if supplier.user_type != 'supplier':
raise ValueError('selected user must be supplier')
super().save(*args, **kwargs)
Upvotes: 0
Reputation: 5337
Have you tried exploring Django's GenericForeignKey
field?
class User(models.Model):
...
limit = models.Q(app_label='your_app_label', model='brand') |
models.Q(app_label='your_app_label', model='creator') |
models.Q(app_label='your_app_label', model='agency')
content_type = models.ForeignKey(ContentType, limit_choices_to=limit, related_name='user_content_type')
object_id = models.UUIDField()
content_object = GenericForeignKey('content_type', 'object_id')
You can access the User's brand/creator/agency by using the following notation:
User.objects.get(pk=1).content_object
This will be an instance of Brand
/Creator
/Agency
as per the content_type
.
class User(models.Model):
...
email = models.EmailField(max_length=255, unique=True)
limit = models.Q(app_label='your_app_label', model='brand') |
models.Q(app_label='your_app_label', model='creator') |
models.Q(app_label='your_app_label', model='agency')
content_type = models.ForeignKey(ContentType, limit_choices_to=get_content_type_choices, related_name='user_content_type')
content_object = GenericForeignKey('content_type', 'email')
Note: Email can not be a nullable field anywhere if you follow this approach! Also this approach seems hacky/wrong since the email
field is now declared in multiple places; and the value can change if you re-assign the content objects. It is much cleaner to link the GenericForeignKey
using the discrete UUIDField
on each of the other three models
account_type
field:ContentType
is expected to be a reference to a Django Model; therefore it requires choices that are Models and not integers.
The function of limit_choices_to
is to perform a filtering such that all possible models are not surfaced as potential GenericForeignKey
class ContentType(models.Model):
app_label = models.CharField(max_length=100)
model = models.CharField(_('python model class name'), max_length=100)
objects = ContentTypeManager()
However, limit_choices_to
does accept callables; so you can write a helper method that translates your account_type
to the correct Model
I am not clear about how this transaltion should work; so I leave that to you.
Upvotes: 7