Chris@1295: class AddUniqueIndexOnTokensValue < ActiveRecord::Migration
Chris@1295:   def up
Chris@1295:     say_with_time "Adding unique index on tokens, this may take some time..." do
Chris@1295:       # Just in case
Chris@1295:       duplicates = Token.connection.select_values("SELECT value FROM #{Token.table_name} GROUP BY value HAVING COUNT(id) > 1")
Chris@1295:       Token.where(:value => duplicates).delete_all
Chris@1295:   
Chris@1295:       add_index :tokens, :value, :unique => true, :name => 'tokens_value'
Chris@1295:     end
Chris@1295:   end
Chris@1295: 
Chris@1295:   def down
Chris@1295:     remove_index :tokens, :name => 'tokens_value'
Chris@1295:   end
Chris@1295: end