Module Sequel::Plugins::Tree
In: lib/sequel/plugins/tree.rb

The Tree plugin adds additional associations and methods that allow you to treat a Model as a tree.

A column for holding the parent key is required and is :parent_id by default. This may be overridden by passing column name via :key

Optionally, a column to control order of nodes returned can be specified by passing column name via :order.

If you pass true for the :single_root option, the class will ensure there is only ever one root in the tree.

Examples: 

  class Node < Sequel::Model
    plugin :tree
  end

  class Node < Sequel::Model
    plugin :tree, :key=>:parentid, :order=>:position
  end

Methods

apply  

Classes and Modules

Module Sequel::Plugins::Tree::ClassMethods
Module Sequel::Plugins::Tree::InstanceMethods
Module Sequel::Plugins::Tree::SingleRoot
Class Sequel::Plugins::Tree::TreeMultipleRootError

Public Class methods

apply(model, opts={})

Create parent and children associations. Any options specified are passed to both associations. You can specify options to use for the parent association using a :parent option, and options to use for the children association using a :children option.

[Source]

    # File lib/sequel/plugins/tree.rb, line 30
30:       def self.apply(model, opts={})
31:         opts = opts.dup
32:         opts[:class] = model
33: 
34:         model.instance_eval do
35:           @parent_column = (opts[:key] ||= :parent_id)
36:           @tree_order = opts[:order]
37:         end
38:         
39:         par = opts.merge(opts.fetch(:parent, {}))
40:         parent = par.fetch(:name, :parent)
41:         model.many_to_one parent, par
42:         
43:         chi = opts.merge(opts.fetch(:children, {}))
44:         children = chi.fetch(:name, :children)
45:         model.one_to_many children, chi
46: 
47:         model.plugin SingleRoot if opts[:single_root]
48:       end

[Validate]