Migrating the Future

• Andrew Godwin, South
• andrew@aeracode.org
• (slides have lots of good diagrams) - http://speakerdeck.com/andrewgodwin/migrating-the-future
• https://github.com/andrewgodwin/django/tree/schema-alteration/
• blog http://aeracode.org/category/django-diaries/

Why replace south?

• 5 years of learning
• poor vcs branching, and merging
• huge migration file size
• migrations sets get too large

south ->

• django.db.migrations - migration commands etc
• django.db.backends.schema - SQL generation, db abstraction

Changes:

• new migration format

  • declarative - so work out state from previous migrations

• dependencies

  • so if two migrations are created on parallel branches, it still works
  • dependencies explicitly stated in files
  • create merge migration, or ask

• squashing (of many old migrations)

  • complications with dependencies between apps

Field API changes coming up - might be backwards incompatible ...