Allow only one instance of a model in Django

Question

I would like to control some configuration settings for my project using a database model. For example:

class JuicerBaseSettings(models.Model):
    max_rpm =         


        

Answer 1

Either you can override save and create a class function JuicerBaseSettings.object()

class JuicerBaseSettings(models.Model):

    @classmethod
    def object(cls):
        return cls._default_manager.all().first() # Since only one item

    def save(self, *args, **kwargs):
        self.id = 1
        return super().save(*args, **kwargs)

============= OR =============

Simply, Use django_solo.

https://github.com/lazybird/django-solo

Snippet Courtsy: django-solo-documentation.

# models.py


from django.db import models
from solo.models import SingletonModel

class SiteConfiguration(SingletonModel):
    site_name = models.CharField(max_length=255, default='Site Name')
    maintenance_mode = models.BooleanField(default=False)

    def __unicode__(self):
        return u"Site Configuration"

    class Meta:
        verbose_name = "Site Configuration"

# admin.py

from django.contrib import admin
from solo.admin import SingletonModelAdmin
from config.models import SiteConfiguration

admin.site.register(SiteConfiguration, SingletonModelAdmin)

# There is only one item in the table, you can get it this way:
from .models import SiteConfiguration
config = SiteConfiguration.objects.get()

# get_solo will create the item if it does not already exist
config = SiteConfiguration.get_solo()