Sequel::Through

This gem extends sequel's associations to provide the ability to create associations that flow through other associations, similar to how :through works in ActiveRecord.

Add this line to your application's Gemfile:

gem 'sequel-through'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sequel-through

# Load the plugin
Sequel::Model.plugin :cyclical_through_associations

class User < Sequel::Model
  one_to_many :user_has_security_groups
  one_to_many :security_groups, through: :user_has_security_groups
  one_to_many :privileges, through: :security_groups
end
class SecurityGroup < Sequel::Model
  one_to_many :security_group_has_privileges
  one_to_many :privileges, through: :security_group_has_privileges
end
class Privilege < Sequel::Model
end
class UserHasSecurityGroup < Sequel::Model
  many_to_one :user
  many_to_one :security_group
  one_to_many :privileges, through: :security_group
end
class SecurityGroupHasPrivilege < Sequel::Model
  many_to_one :security_group
  many_to_one :privilege
end

# Solve any cyclical dependencies (when :cyclical_through_associations is used)
Sequel::Model.solve_cyclical_associations!

# Use the intermediate associations
User.first.security_groups # => [#<SecurityGroup 1>, #<SecurityGroup 2> ...]
User.first.privileges # => [#<Privilege A>, #<Privilege B> ...]

This plugin adds an optional :through key for *_to_one and *_to_many associations. When :through is provided, intermediary associations are traversed and a single one_through_many or many_through_many association is added to the base model using a JOIN structure calculated from the associations traversed.

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/kenaniah/sequel-through.

The gem is available as open source under the terms of the MIT License.