RemVee.blog

Remco @ Safe data migrations

Remco — Thu, 10 Apr 2008 01:39:47 +0200

Digging through commit logs I noticed I didn’t even try a nested class assuming I would just reopen the original. Actually I was so freaked by the problems my migration caused I even moved to using SQL for a while. How embarrassing.. Thanks for the heads up!

coderrr @ Safe data migrations

coderrr — Wed, 09 Apr 2008 18:18:01 +0200

I don’t think you need to remove and redefine the class in the global scope. You can instead just define the class inside of your migration class:

class SomeMigration < AR::M
  class User < AR::B
    has_many :roles
  end
  class Role < AR::B
    belongs_to :user
  end

  def self.up
    ...
    User.find(:all).each{|u| u.roles.create(...) }
  end
end

The benefit of this is that the original model class is unaffected. Was there some case you found where this did not work?

http://coderrr.wordpress.com

Marcel @ Safe data migrations

Marcel — Wed, 09 Apr 2008 06:40:10 +0200

Lol, apparently your blog supports some sort of formatting. My stylish double-dash applied a strike-through to my text…

Marcel @ Safe data migrations

Marcel — Wed, 09 Apr 2008 06:39:06 +0200

Nice (and useful!) abstraction applied in our last project (where Remco came up with this when we were dealing with lots of data migrations).
I’m sure this little piece of code has — and, in the future, will — save me a lot of trouble. Thanks!