dm-is-reflective

gem 'dm-is-reflective',
  :git => 'git://github.com/godfat/dm-is-reflective.git',
  :submodules => true

require 'dm-is-reflective' # this would require 'dm-core'
dm = DataMapper.setup :default, 'sqlite::memory:'

class User
  include DataMapper::Resource
  is :reflective

  # map all, returning an array of properties indicating fields it mapped
  reflect /.*/  # e.g. => [#<Property:#<Class:0x18f89b8>:id>,
                #          #<Property:#<Class:0x18f89b8>:title>,
                #          #<Property:#<Class:0x18f89b8>:body>,
                #          #<Property:#<Class:0x18f89b8>:user_id>]

  # map all (with no argument at all)
  reflect

  # mapping for field name ended with _at, and started with salt_
  reflect /_at$/, /^salt_/

  # mapping id and email
  reflect :id, :email

  # mapping all fields with type String, and id
  reflect String, :id

  # mapping login, and all fields with type Integer
  reflect :login, Integer
end

# there's no guarantee of the order in storages array
dm.storages
# => ['users']

# show all indices
dm.indices('users') # [:id, {:unique_index => :users_pkey}]

# there's no guarantee of the order in fields array
User.fields
# => [[:created_at,  DateTime, {:required => false}],
      [:email,       String,   {:required => false, :length => 255,
                                :default  => 'nospam@nospam.tw'}],
      [:id,          Serial,   {:required => true, :serial => true,
                                :key      => true}],
      [:salt_first,  String,   {:required => false, :length => 50}],
      [:salt_second, String,   {:required => false, :length => 50}]]

dm.fields('users').sort_by{ |field| field.first.to_s } ==
       User.fields.sort_by{ |field| field.first.to_s }
# => true

dm.storages_and_fields
# => {'users' => [[:id,          Serial,   {:required => true,
                                            :serial   => true,
                                            :key      => true}],
                  [:email,       String,   {:required => false,
                                            :default  =>
                                              'nospam@nospam.tw'}],
                  [:created_at,  DateTime, {:required => false}],
                  [:salt_first,  String,   {:required => false,
                                            :length   => 50}],
                  [:salt_second, String,   {:required => false,
                                            :length   => 50}]]}

# there's no guarantee of the order in returned array
dm.auto_genclass!
# => [DataMapper::Is::Reflective::User,
      DataMapper::Is::Reflective::SchemaInfo,
      DataMapper::Is::Reflective::Session]

# you can change the scope of generated models:
dm.auto_genclass! :scope => Object
# => [User, SchemaInfo, Session]

# you can generate classes for tables you specified only:
dm.auto_genclass! :scope => Object, :storages => /^phpbb_/
# => [PhpbbUser, PhpbbPost, PhpbbConfig]

# you can generate classes with String too:
dm.auto_genclass! :storages => ['users', 'config'], :scope => Object
# => [User, Config]

# you can generate a class only:
dm.auto_genclass! :storages => 'users'
# => [DataMapper::Is::Reflective::User]

# you can also generate the source from models:
puts User.to_source