South: Migrations for Django

The very first public presentation of South, at the Schema Evolution panel at DjangoCon 2008. Video at https://www.youtube.com/watch?v=VSq8m00p1FM

Transcript

1. south migrations for django
   south.aeracode.org
   

   View Slide

2. south migrations for django
   Why?
   1. Migrations are essential.
   2. Branched development/
   missing migrations
   3. Inter-app dependencies
   4. Database abstraction needed too!
   

   View Slide

3. south migrations for django
   syncdb
   dropdb
   syncdb
   time
   create initial models
   add new fields
   create
   create
   create
   syncdb
   create
   create
   create
   

   View Slide

4. south migrations for django
   syncdb
   dropdb
   syncdb
   time
   create initial models
   add new fields
   create
   create
   create
   syncdb
   create
   create
   create
   south
   createmigration
   --initial
   migrate
   create
   create create
   write new
   migration
   migrate
   alter alter
   alter
   

   View Slide

5. south migrations for django
   database independence
   class Migration:
   def forwards(self):
   # Model 'Category'
   db.create_table('aeblog_category', (
   ('id', models.AutoField(
   verbose_name='ID',
   primary_key=True,
   auto_created=True,
   )),
   ('title', models.CharField(max_length=255)),
   ('slug', models.SlugField())
   ))
   

   View Slide

6. south migrations for django
   missing migrations
   001_foo
   002_bar
   003_baz
   004_phou
   001_foo
   002_bar
   003_baz
   001_foo
   002_bar
   003_baz
   004_phou
   001_foo
   002_bar
   003_baz
   004_fizz
   001_foo
   002_bar
   003_baz
   004_fizz
   001_foo
   002_bar
   003_baz
   > >
   >
   >
   >
   

   View Slide

7. south migrations for django
   missing migrations
   004_phou
   001_foo
   002_bar
   003_baz
   004_fizz
   001_foo
   002_bar
   003_baz
   > 004_fizz
   001_foo
   002_bar
   003_baz
   004_phou
   > south: problem detected,
   --merge fixes it
   global number (e.g. rails):
   problem never found
   

   View Slide

8. south migrations for django
   dependencies
   001_forum
   002_post
   003_add_date
   have to migrate in
   correct order
   004_pictures
   001_initial
   002_add_code
   003_pictures
   

   View Slide

9. south migrations for django
   dependencies
   001_forum
   002_post
   003_add_date
   have to migrate in
   correct order
   004_pictures
   001_initial
   002_add_code
   003_pictures
   1 2
   3
   4
   5
   6
   7
   

   View Slide

10. south migrations for django
    quick demo
    

    View Slide