I don't use ORMs in node, but in general there are two different types of ORMs

• the active record approach which contains the needed buisness logic inside of the Model. martinfowler.com/eaaCatalog/activeRecord.html
• the datamapper approach which only uses a dumb dataobject and has the domain separated. martinfowler.com/eaaCatalog/dataMapper.html

Those are the two main approaches.

There are however still some other more generic approaches like the table data gateway martinfowler.com/eaaCatalog/tableDataGateway.html and the row data gateway.

this is more of a general approach :) .... but hey better than nothing :P