Some considerations for Ruby on Rails migrations _ruby topics

Keep the schema.rb under version control.
Use Rake db:scheme:load instead of rake db:migrate to initialize the empty database.
Use rake db:test:prepare to update the schema of the test database.

Avoid setting default data in the table. Use the model layer to replace.

  def amount
   Self[:amount] or 0
  end

However, the use of self[:attr_name] is considered quite common, and you may also consider replacing it with a more verbose (arguably more readable) Read_attribute:

def amount
   Read_attribute (: Amount) or 0
  end

When writing a constructive migration (join a table or field), migrate using the new method of Rails 3.1-replace the up and down method with the change method.

 # The way it used to be
  class Addnametoperson < activerecord::migration
   def up
    add_column:p ersons,: Name,: String
   End

   def down
    remove_column:p erson,: Name
   end

  # New Preferences
  class Addnametoperson < Activerecord::migration
   def change
    add_column:p ersons,: Name,: string
   end