rails 3.2 migration cannot add index to create_table in change method

Question

here is my migration in rails 3.2.2:

class CreateStatistics < ActiveRecord::Migration   def change     create_table :statistics do |t|       t.string :name       t.integer :item_id       t.integer :value       t.text :desc        t.timestamps       t.index [:name, :item_id]     end    end end 

and here is the migrate error:

==  CreateStatistics: migrating =============================================== -- create_table(:statistics) ActiveRecord::ConnectionAdapters::TableDefinition rake aborted! An error has occurred, all later migrations canceled:  undefined method `index' for #<ActiveRecord::ConnectionAdapters::TableDefinition:0xbd16888>  Tasks: TOP => db:migrate (See full trace by running task with --trace) 

what is the right way to create a index?

Answer 1

You can still add an index as a part of a "change" migration. You just have to do it outside of the call to create_table:

class CreateStatistics < ActiveRecord::Migration   def change     create_table :statistics do |t|       t.string :name       t.integer :item_id       t.integer :value       t.text :desc        t.timestamps     end      add_index :statistics, [:name, :item_id]   end end 

This correctly creates the table and then the index on an "up" migration and drops the index and then the table on a "down" migration.

Answer 2

so I change it to the old way, and it works. and I think there is a new way doing this by using change method.

class CreateStatistics < ActiveRecord::Migration   def up     create_table :statistics do |t|       t.string :name       t.integer :item_id       t.integer :value       t.text :desc        t.timestamps     end     add_index :statistics, [:name, :item_id]   end    def down     drop_table :statistics   end end