sql_debug.txt

Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.002120) DROP TABLE IF EXISTS "users"
Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.001219) DROP TABLE IF EXISTS "addresses"
Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.003135) CREATE TABLE "users" ( "id" SERIAL NOT NULL PRIMARY KEY, "username" VARCHAR(50) NOT NULL, "age" SMALLINT NOT NULL )
Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.002443) CREATE TABLE "addresses" ( "id" SERIAL NOT NULL PRIMARY KEY, "user_id" INTEGER NOT NULL, "street" VARCHAR(50) NOT NULL, "zipcode" VARCHAR(10) NOT NULL, "city" VARCHAR(50) NOT NULL )
Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.000816) INSERT INTO "users" ("id", "username", "age") VALUES (1, 'John', 18)
Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.000443) INSERT INTO "users" ("id", "username", "age") VALUES (2, 'Jane', 21)
Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.000532) INSERT INTO "addresses" ("id", "user_id", "street", "zipcode", "city") VALUES (1, 1, 'Street 1/2', 'Chicago', '12345')
Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.000463) INSERT INTO "addresses" ("id", "user_id", "street", "zipcode", "city") VALUES (2, 2, 'Street 2/4', 'Boston', '67890')
Tue, 14 Feb 2012 14:56:18 GMT ~ debug ~ (0.001570) SELECT "age", "username", "id", "street", "zipcode", "user_id", "city" FROM (SELECT * FROM "users" AS "left" NATURAL JOIN (SELECT * FROM "addresses" WHERE "city" = 'Boston') AS "right") AS "users_addresses" WHERE "city" = 'Boston'

veritas_join_and_restrict_spec.rb

require 'spec_helper'

describe 'join and restrict' do
  before(:all) do
    setup_db

    insert_user 1, 'John', 18
    insert_user 2, 'Jane', 21

    insert_address 1, 1, 'Street 1/2', 'Chicago', '12345'
    insert_address 2, 2, 'Street 2/4', 'Boston',  '67890'

    DataMapper.relation_registry << Veritas::Relation::Gateway.new(
      DATABASE_ADAPTER, Address::Mapper.base_relation)

    DataMapper.relation_registry << Veritas::Relation::Gateway.new(
      DATABASE_ADAPTER, User::Mapper.base_relation)
  end

  let(:operation) do
    left  = DataMapper.relation_registry[:users]
    right = DataMapper.relation_registry[:addresses].restrict { |r| r.city.eq('Boston') }

    left.join(right)
  end

  class Address
    attr_reader :id, :street, :zipcode, :city

    def initialize(attributes)
      @id, @street, @zipcode, @city = attributes.values_at(:id, :name, :zipcode, :city)
    end

    class Mapper < DataMapper::Mapper::VeritasMapper
      map :id,      :type => Integer
      map :user_id, :type => Integer
      map :street,  :type => String
      map :zipcode, :type => String
      map :city,    :type => String

      model Address
      name :addresses
    end
  end

  class User
    attr_reader :id, :name, :age

    def initialize(attributes)
      @id, @name, @age = attributes.values_at(:id, :name, :age)
    end

    class Mapper < DataMapper::Mapper::VeritasMapper
      map :id, :type => Integer
      map :name, :to => :username, :type => String
      map :age, :type => Integer

      model User
      name :users
    end
  end

  it 'finds user with a specific address' do
    users = User::Mapper.new(operation.restrict { |r| r.city.eq('Boston') }.optimize).to_a
    user  = users.first

    users.should have(1).item

    user.should be_instance_of(User)
    user.name.should eql('Jane')
  end

end

@dkubb I just pushed this spec to dm-mapper