Wow. Thank you Rick. Very nice explanation. Yeah, I dropped the columns by raking 'down' and have also deleted that migration, so I think I'm good to go now. Also, I don't use textmate, but yeah, I made sure that the "down" migration removed all the columns the "up" created.
Thank you again Mr. Rick On Apr 7, 10:36 am, Rick DeNatale <[email protected]> wrote: > On Tue, Apr 6, 2010 at 11:29 PM, Ryan Waldron <[email protected]> wrote: > > You'll also need to remove that migration's entry from the > > 'schema_migrations' table. That's how Rails keeps up with what > > migrations exist, and whether it's done them all. > > Running rake db:migrate:down VERSION=XXX should remove the entry. > > Otherwise rake db:migrate wouldn't run the migration again. A normal > use case for migrate down is: > > rake db:migrate > > #oops something was wrong in migration 123456 > rake db:migrate:down VERSION=123456 > edit db/migrate/123456_whatever_it_does > rake db:migrate > > > On Tue, Apr 6, 2010 at 10:10 PM, GoodGets <[email protected]> wrote: > >> What exactly does rake db:migrate:down VERSION=XXX do? I understand > >> that it runs the "down" migration, completely removing any columns/ > >> tables that migration may have created, > > Well it does whatever YOU told it to in the down part of the > migration. It's up to you (or whatever you use to edit/generate the > migration) to write the correct code there. > > I tend to use Textmate snippets from the rails bundle to do > migrations, and the table/column migration snippets will generate > 'undo' code in the down migration when you expand them in the up > migration. But YMMV depending on what tools you use. > > >> but does this mean that I can > >> can delete these migration files as well? I'd like for Rails to have > >> no knowledge of their existence. (I was allowing user profile pics > >> with Paperclip, but have since decided to just use their Gravatars.) > >> I know you can delete a migration, and even delete those columns from > >> the schema, but Rails still "remembers" these changes and just updates > >> them the next time you rake db:migrate. So, I'd like to completely > >> rid my app of a particular migration, is rake db:migrate:down then > >> deleting that migration from the migrate folder the way to do it? > > When you do rake db:migration the rake task looks for migrations > under db/migrate which don't have entries in the schema_migrations > table, and runs those (actually I think it's a bit more subtle than > that, there's been discussion of a 'bug' which can make the task > ignore migrations with a timestamp older than the newest one in > schema_migrations, which can keep migrations merged from another > branch NOT to be run. But... > > If you run > > rake db:migrate:down version=XXX > > and then remove the file db/migrate/XXX_whatever from your source, the > rake task won't see it and it will be gone. > > -- > Rick DeNatale > > Blog:http://talklikeaduck.denhaven2.com/ > Github:http://github.com/rubyredrick > Twitter: @RickDeNatale > WWR:http://www.workingwithrails.com/person/9021-rick-denatale > LinkedIn:http://www.linkedin.com/in/rickdenatale -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
