umbra:dm-spec ted$ irb
>> require 'dm-core'
=> true
>> require 'many_through_models'
=> true
>>
?> DataMapper.setup(:default, "mysql://localhost/dm_pets")
=> #<DataMapper::Adapters::MysqlAdapter:0x1903868 @resource_naming_convention=DataMapper::NamingConventions::Resource::UnderscoredAndPluralized, @uri=#<struct DataObjects::URI scheme="mysql", user=nil, password=nil, host="localhost", port=nil, path="/dm_pets", query=nil, fragment=nil>, name:default, transactions{}, field_naming_conventionDataMapper::NamingConventions::Field::Underscored
>> Human.all(Human.ownerships.pet.name => "Bo")
=> [#<Human id=1 first_name="Barack" middle_name=nil last_name="Obama">, #<Human id=2 first_name="Michelle" middle_name=nil last_name="Obama">, #<Human id=3 first_name="Malia" middle_name=nil last_name="Obama">, #<Human id=4 first_name="Sasha" middle_name=nil last_name="Obama">]
>> Human.all(Human.pets.name => "Bo")
ArgumentError: Unknown property 'name'
	from /Library/Ruby/Gems/1.8/gems/dm-core-0.9.11/lib/dm-core/query.rb:667:in `method_missing'
	from (irb):6