Skip to content

Creating automatic migrations for Views models witch working reverse and full command options like in normal makemigrations

License

Notifications You must be signed in to change notification settings

LECbg/django-db-views

 
 

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 

History

35 Commits
 
 
 
 
 
 
 
 
 
 
 
 

Repository files navigation

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?

  • To create your view use DBView class, remember to set view definition attribute.

    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'
    
  • The view definition must be a string or a callable. Callable view definition example:

    view_definition = lambda: str(SomeModel.objects.all().query)

using callable allow you to write view definition using ORM.

How view migrations work?

  • DBView working as regular django model. You can use it in any query.
  • 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 projects based on Django: 1.11.5, 2.2.10

About

Creating automatic migrations for Views models witch working reverse and full command options like in normal makemigrations

Resources

License

Stars

Watchers

Forks

Releases

No releases published

Packages

No packages published

Languages

  • Python 100.0%