DataMapper Quick Reference

datamapper.rb

# some more: http://cheat.errtheblog.com/s/datamapper/

# results of first steps with datamapper and lack of documentation

# use a bigint unsigned column as primary key
property :id,               Serial, :min => 0, :max => 2**32

# automagically create database from your model definitions (destructive !)
DataMapper.auto_migrates!
<Model>.auto_migrate!

# try to migrate schema doing required changes (data are safe but this method seems rather limited in what can be done)
DataMapper.auto_upgrade!
<Model>.auto_upgrade!


# define hooks

before(:create) { ... } # unlike activerecord the block is called in the object context, self point to the object not the class

before(:create, :assign_something) # call the method on the object

after(:create) { ... }

valid phases are:
:create
:update
:destroy


# set the default database for a given model
class User
  def self.default_repository_name
    :other
  end
end