ROR migration cheat cheet

ROR migrations

(ActiveRecord::Migration) 

=== migration options

add_column
add_index
change_column
change_table
create_table
drop_table
remove_column
remove_index
rename_column

=== suported data types

:binary
:boolean
:date
:datetime
:decimal
:float
:integer
:primary_key
:string
:text
:time
:timestamp


=== create migration 

rails generate model Product name:string description:text

=== references

create_table :products do |t|
  t.references :category
end

=== running a specific version of a migration 

rake db:migrate VERSION=20080906120000

=== rollback migration

rake db:rollback

rake db:rollback STEP=3

rake db:migrate:up VERSION=20080906120000