diff options
Diffstat (limited to 'activerecord/lib')
| -rw-r--r-- | activerecord/lib/active_record/migration.rb | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb index 5bfa00c19a..6f9b0ee2b4 100644 --- a/activerecord/lib/active_record/migration.rb +++ b/activerecord/lib/active_record/migration.rb @@ -120,6 +120,21 @@ module ActiveRecord # execute "ALTER TABLE `pages_linked_pages` DROP INDEX `page_id_linked_page_id`" # end # end + # + # == Using the class after changing table + # + # Some times you'll want to add a column in a migration and populate it immediately after. In that case, you'll need + # to make a call to Base#reset_column_information in order to ensure that the class has the latest column data from + # after the new column was added. Example: + # + # class MakeJoinUnique < ActiveRecord::Migration + # def self.up + # add_column :people, :salary, :integer + # Person.find(:all).each do |p| + # p.salary = SalaryCalculator.compute(p) + # end + # end + # end class Migration class << self def up() end |