ORM Adapter <img src=“https://secure.travis-ci.org/ianwhite/orm_adapter.png?branch=master” alt=“Build Status” />

Provides a single point of entry for popular ruby ORMs. Its target audience is gem authors who want to support more than one ORM.

Example of use

require 'orm_adapter'

User # is it an ActiveRecord, DM Resource, MongoMapper or MongoId Document?

User.to_adapter.find_first :name => 'Fred' # we don't care!

user_model = User.to_adapter
user_model.get!(1)                      # find a record by id
user_model.find_first(:name => 'fred')  # find first fred
user_model.find_first(:level => 'awesome', :id => 23)
                                        # find user 23, only if it's level is awesome
user_model.find_all                     # find all users
user_model.find_all(:name => 'fred')    # find all freds
user_model.find_all(:order => :name)    # find all freds, ordered by name
user_model.create!(:name => 'fred')     # create a fred 
user_model.destroy(object)              # destroy the user object

@see OrmAdapter::Base for more details of the supported API

Supported ORMs

Currently supported ORMs are ActiveRecord, DataMapper, MongoMapper, and MongoId.

We welcome you to write new adapters as gems. ORM Adapter will stay focused in having these major ORMs working.

To write an adapter look at lib/orm_adapter/adapters/active_record.rb for an example of implementation. To see how to test it, look at spec/orm_adapter/example_app_shared.rb, spec/orm_adapter/adapters/active_record_spec.rb. You’ll need to require the target ORM in spec/spec_helper.rb

Goals

ORM Adapter’s goal is to support a minimum API used by most of the plugins that needs agnosticism beyond Active Model.

ORM Adapter will support only basic methods, as get, find_first, create! and so forth. It is not ORM Adapter’s goal to support different query constructions, handle table joins, etc.

ORM adapter provides a consistent API for these basic class or ‘factory’ methods. It does not attempt to unify the behaviour of model instances returned by these methods. This means that unifying the behaviour of methods such as ‘model.save`, and `model.valid?` is beyond the scope of orm_adapter.

If you need complex queries, we recommend you to subclass ORM Adapters in your plugin and extend it expressing these query conditions as part of your domain logic.

History

orm_adapter is an extraction from pickle by Ian White. Pickle’s orm adapter included work by Daniel Neighman, Josh Bassett, Marc Lee, and Sebastian Zuchmanski.

José Valim suggested the extraction, and worked on the first release with Ian.

Luke Cunningham contributes the Mongo Mapper adapter.

Fred Wu contributes the #destroy methods, and :limit, :offset options for #find_all

Tim Galeckas

Development

To run the specs, you can start from the last known good set of gem dependencies in Gemfile.lock.development: