An awesome nested set implementation for Active Record

Ancestry allows the records of a ActiveRecord model to be organized in a tree structure, using a single, intuitively formatted database column. It exposes all the standard tree structure relations (ancestors, parent, root, children, siblings, descendants) and all of them can be fetched in...

A gem that adds simple support for organizing ActiveRecord models into parent–children relationships.

NOTICE: official repository moved to https://github.com/bbommarito/acts_as_nested_set

Easily and efficiently make your ActiveRecord model support hierarchies

ActiveRecord extension for sorted adjacency lists support

Arboreal is yet another extension to ActiveRecord to support tree-shaped data structures. Internally, Arboreal maintains a computed "ancestry_string" column, which caches the path from the root of a tree to each node, allowing efficient retrieval of both ancestors and descendants. Arboreal surf...

Adds directed acyclic graph functionality to ActiveRecord.