django-db-views

How to install?

• pip install django-db-views

How to use?

• add django_db_views to INSTALLED_APPS
• use makeviewmigrations command to create migrations for view models

How to create view in your database?

from django_db_views.db_view import DBView

class Balance(DBView):

    virtual_card = models.ForeignKey(
        VirtualCard, on_delete=models.DO_NOTHING, related_name='virtual_cards'
    )
    total_discount = models.DecimalField(max_digits=12, decimal_places=2)
    total_returns = models.DecimalField(max_digits=12, decimal_places=2)
    balance = models.DecimalField(max_digits=12, decimal_places=2)
    
    view_definition = """
        SELECT
            row_number() over () as id,  # Django requires column called id
            virtual_card.id as virtual_card_id,
            sum(...) as total_discount,
        ...
    """

    class Meta:
        managed = False
        db_table = 'virtual_card_balance'

How view migrations work?

• It's using Django code, view-migrations looks like regular migrations.
• It relies on db_table names.
• makeviewmigrations command finds previous migration for view.
  • if there is no such migration then script create a new migration
  • if previous migration exists but no change in view_definition is detected nothing is done
  • if previous migration exists, then script will use previous view_definition for backward operation, and creates new migration.

Tested with live project based on Django 1.11.5