class CreateCategories < ActiveRecord::Migration
  def up
    create_table :categories do |t|
      t.integer :parent_id
      t.string  :title, :null => false
    end
    execute('CREATE UNIQUE INDEX ix_categories_root_title ON categories (title) WHERE parent_id IS NULL')
  end
  def down
    drop_table :categories
  end
end

ActiveRecord::Schema.define(:version => 20110808161830) do
  create_table "categories", :force => true do |t|
    t.integer "parent_id"
    t.string  "title", :null => false
  end
  add_index "categories", ["title"], :name => "ix_categories_root_title", :unique => true
end

config.active_record.schema_format = :sql