感觉 dm 有一些优点，隔离数据库，方便单元测试。用的是 include 方式，避免了继承。
require 'dm-core'
require 'dm-migrations'
# Open the database test1.db
DataMapper.setup :default, "sqlite3://#{Dir.pwd}/test1.db"
# Define the Person model
class Person
include DataMapper::Resource
property :firstname, String
property :lastname, String
property :email, String, :key => true
end
# Automatically create the tables if they don't exist
DataMapper.auto_migrate!
# Create a new record
p = Person.new
p.attributes = {
:firstname => 'John',
:lastname => 'Doe',
:email => '[email protected]'
}
# Save it to the database
p.save
# Make some changes to the object
p.lastname = 'Smith'
p.save
# Create a new object and destroy it
p2 = Person.new
p2.email = '[email protected]'
p2.save
p2.destroy
# Find a record from the database
p3 = Person.get('[email protected]')
puts p3.inspect
