1

I am creating a project in django and django rest framework. Its an api for an angular app. The database setup consists of multiple databases. one is default database, all the django tables reside in this database; rest of the databases belong to a type of a user, each user is supposed to have a separate database. So, all the user related data goes to its separate database. To implement the selecting database dynamically, user object has an extra field to store the database to write to.

from django.contrib.auth.models import AbstractUser

class CustomUser(AbstractUser):
    """Custom User model."""

    database= models.CharField(max_length=9)

Reason for doing this was performance improvement as each database is separate, ListView and DetailView would work faster than if the data was stored in the one database only.

I know I can choose a database to store by using the using method on the model manager. In the rest api things work fine and data is being stored in their separate databases, but I end up overriding methods that django has defined. Its adding development cost to the project. Foreign keys and ManytoMany keys needs to be resolved with the current database of the user, which is not happening as I have customized the database setup. Also, my code cant be as good as theirs :p , as they have written django over the course of many years.

I have overwritten many querysets already, but django still uses default database many times. If only I could use the request object in the model manager of django models to swap the default database on per request basis, things would be different i think.

My questions are -

  1. Is there a way to access the request object in the model manager? I could do something to the effect of below code.

    class CustomManager(models.Manager):

    def get_queryset(self, request):

    return super(CustomManager, self).using(request.user.database).get_queryset()

  2. Model manager has _db property that could be used to select database. Would overriding it is advised? if yes, how and where in the code?

  3. Is there a better way to implement the separate databases?

Thanks in advance.

Regards

RyuCoder
  • 1,714
  • 2
  • 13
  • 21

1 Answers1

1

Using a database router is recommended in Django docs, but the problem is it only accesses the model class.

Found a couple of questions related to the problem of switching databases dynamically. This post has a solution that would solve the problem of passing the request.user or any other parameter by using a threading.local instance.

Someone created a reusable plugin even for this - https://github.com/ambitioninc/django-dynamic-db-router

Hope that helps.

svemaraju
  • 90
  • 7