Chris@1464: class AddUniqueIndexOnTokensValue < ActiveRecord::Migration
Chris@1464:   def up
Chris@1464:     say_with_time "Adding unique index on tokens, this may take some time..." do
Chris@1464:       # Just in case
Chris@1464:       duplicates = Token.connection.select_values("SELECT value FROM #{Token.table_name} GROUP BY value HAVING COUNT(id) > 1")
Chris@1464:       Token.where(:value => duplicates).delete_all
Chris@1464:   
Chris@1464:       add_index :tokens, :value, :unique => true, :name => 'tokens_value'
Chris@1464:     end
Chris@1464:   end
Chris@1464: 
Chris@1464:   def down
Chris@1464:     remove_index :tokens, :name => 'tokens_value'
Chris@1464:   end
Chris@1464: end