Hi all, I gave a talk to a local user-group about the migrations in 1.7, and some people in the audience raised things they would like to be able to do, and are not supported by the current framework; thought it would be nice to bring them here.
Two issues were about handling migrations at the project level rather than app level: 1) Cross-app migrations. The act of moving a model from one app to another should be a common-enough refactoring; especially for beginners, breaking a piece of an app out to a separate app is something a user is very likely to want. Current migrations, being app-oriented, make this possible, but a little awkward. 2) Roll back project to point in history. This is requested by people who want to work on feature branches (or any separate branches, each with its own migrations). It is a bit of a hard problem I've run int myself, and I suspect it requires some integration with source-control systems to be done right. The solution I recommended (and used) was to keep separate databases for separate branches, but that is quite cumbersome in a large project. The third issue is an intriguing idea. It was presented as "keep more than one state of migration history in the database", but I think that a general multiple-migration-history mechanism is neither required nor sufficient for the user's goal. What he wanted was: 3) Separate "destructive" migrations from "non-destructive" -- if I got it right, "destructive" in the sense that "the old code can no longer work with the database after the migration". So, adding a nullable column, or a new table, would generally be non-destructive. If you have several servers running on the same database, with this separation you can do a rolling upgrade -- first make non-destructive changes, then upgrade the servers one by one, and only when they all have the new code, do the destructive migration. Your comments are welcome, Shai. -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at http://groups.google.com/group/django-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/201409240154.08524.shai%40platonix.com. For more options, visit https://groups.google.com/d/optout.
