datamapper

I'm working on a Rails 3.2 app that uses Datamapper as its ORM. I'm looking for a way to sort a result set by an attribute of the associated model. Specifically I have the following models: class Vehicle include DataMapper::Resource belongs_to :user end class User include DataMapper::Resource has n, :vehicles end Now I want to be able to query the vehicles and sort them by the name of the driver. I tried the following but neither seems to work with Datamapper: > Vehicle.all( :order => 'users.name' ) ArgumentError: +options[:order]+ entry "users.name" does not map to a property in Vehicle >

For some reason, heroku tries to require dm-sqlite-adapter, even though it should use Postgres here. Note, that this happens when I open any URL - not during the git push itself. I built a default facebook app. The Gemfile: source :gemcutter gem "foreman" gem "sinatra" gem "mogli" gem "json" gem "httparty" gem "thin" gem "data_mapper" gem "heroku" group :production do gem "pg" gem "dm-postgres-adapter" end group :development, :test do gem "sqlite3" gem "dm-sqlite-adapter" end Datamapper setup: # Setting up the database DataMapper.setup(:default, ENV['DATABASE_URL'] || "sqlite3://#{Dir.pwd}

I'm sing the Data Mapper Pattern in Zend Framework. This works well so far, but now I got to a point where I need your help/opinion. So let's start with the Code: We got a table with several Persons: CREATE TABLE `persons` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(50) NOT NULL, `age` int(3) NOT NULL, `haircolor` varchar(20) DEFAULT NULL, PRIMARY KEY (`id``), ); Now I try to select all people, that have brown hair. I use the following method in the ServiceLayer public function getPeopleByHaircolor($hair) { return $this->getMapper()->fetch('haircolor = ?', $hair); } The method in

I'm reading the architectural patterns chapter of POEAA, and Fowler says that "As the domain logic gets more complicated and you begin moving toward a rich Domain Model (116), the simple approach of an Active Record (160) starts to break down. The one-to-one match of domain classes to tables starts to fail as you factor domain logic into smaller classes. Relational databases don't handle inheritance, so it becomes difficult to use strategies [Gang of Four] and other neat OO patterns. As the domain logic gets feisty, you want to be able to test it without having to talk to the database all the

I've come across a couple of ORMs that recently announced they are planning to move their implementation from Active Record to Data Mapper. My knowledge of this subject is very limited. So a question for those who know better, is Data Mapper newer than Active Record? Was it around when the Active Record movement started? How do the two relate together? Lastly since I'm not a database person and know little about this subject, should I follow an ORM that's moving to the Data Mapper implementation, as in what's in it for me as someone writing software (not a data person)? Gordon The DataMapper

I am working on a simple app in Sinatra with DataMapper. I want to see the queries that DM is created for my various chained finders, etc. I have tried: DataMapper::Logger.new(STDOUT, :debug) in my configure do ... end block in an environment.rb file that loads when the app is started. I have also tried: DataMapper::Logger.new('log/my-app.log', :debug) Neither yields log statements from the app accessed either through a browser or through an irb session that requires my app. I do see the app starting message. I am using rackup config.ru to run the app locally. What am I missing? It seems that