Enhances ActiveRecord with nested hierarchies.
Latest commit ef78d38 Jun 18, 2016 @bkuhlmann Updated gem dependencies.



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A implementation of the Closure Table pattern for ActiveRecord models. This uses two tables to maintain the ancestor/descendant relationship for all branches of a particular model. For example, you might have web pages you want to represent in a nested hierarchy which would yield the following table structure:

  • Page (i.e. pages)
  • PageBranch (i.e. page_branches)

Assuming the following page hierarchy:

Branch Graph

The page_branches table would consist of the following data:

Branch Table

Table of Contents


  • Database integrity via the Closure Table pattern.


  1. MRI 2.x.x.
  2. Ruby on Rails 4.x.x.


For a secure install, type the following from the command line (recommended):

gem cert --add <(curl --location --silent https://www.alchemists.io/gem-public.pem)
gem install lineage --trust-policy MediumSecurity

NOTE: A HighSecurity trust policy would be best but MediumSecurity enables signed gem verification while allowing the installation of unsigned dependencies since they are beyond the scope of this gem.

For an insecure install, type the following (not recommended):

gem install lineage

Add the following to your Gemfile:

gem "lineage"


Add the following to any model you wish to enable with lineage support:



To test, run:

bundle exec rake


Read Semantic Versioning for details. Briefly, it means:

  • Patch (x.y.Z) - Incremented for small, backwards compatible bug fixes.
  • Minor (x.Y.z) - Incremented for new, backwards compatible public API enhancements and/or bug fixes.
  • Major (X.y.z) - Incremented for any backwards incompatible public API changes.

Code of Conduct

Please note that this project is released with a CODE OF CONDUCT. By participating in this project you agree to abide by its terms.


Read CONTRIBUTING for details.


Copyright (c) 2010 Alchemists. Read the LICENSE for details.


Read the CHANGELOG for details. Built with Gemsmith.


Developed by Brooke Kuhlmann at Alchemists