I'm trying out the migrations in Django 1.7 and I was surprised when my migrations did not set default values in the database. Can someone share the motivation for this functionality? (more details below)
This was surprising given the documentation I read: 1. the release notes <https://docs.djangoproject.com/en/1.7/topics/migrations/#postgresql> for 1.7 suggest using `null=True` for new database columns, but only because of the potential performance impact during a site update (which seems odd, since the migrations don't set default values anyways…) 2. the example of a migration <https://docs.djangoproject.com/en/1.7/topics/migrations/#migration-files> file clearly shows a default value of `0` for the Author.rating field, even though it turns out the default isn't used Running `python manage.py sqlmigrate appname migrationnumber` for an example like the Author.rating addition in the docs would look something like this: BEGIN; ALTER TABLE "author" ADD COLUMN "rating" integer NOT NULL DEFAULT 0; ALTER TABLE "author" ALTER COLUMN "rating" DROP DEFAULT; COMMIT; However, looking in the source code <https://github.com/django/django/blob/master/django/db/backends/schema.py#L381>, I can see: "(Django usually does not use in-database defaults)". I find it quite problematic for production site updates, since my updates generally look like: 1. generate migrations 2. run migrations on prod db, while old webserver code is still running 3. after migrations, update webserver I cannot afford to have breaking problems between steps 2 & 3 if I want to add a new db column that is not null and has a default value. Does anyone here know the motivation for the existing no-defaults-in-the-db functionality? I'd like to know, since I'm putting together a backend derived from 'django.db.backends.postgresql_psycopg2' that is exactly the same, except for setting default values in the db, and I'd like to know what concerns there might be for a backend like this? -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at http://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/147340fc-04bc-44c9-aa0a-230635b48d0b%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
