Module: Ltree::Hierarchy

Defined in:
lib/ltree_hierarchy/version.rb,
lib/ltree_hierarchy/hierarchy.rb

Defined Under Namespace

Modules: InstanceMethods

Constant Summary collapse

VERSION = 
"0.0.6"

Instance Method Summary collapse

Instance Method Details

#at_depth(depth) ⇒ Object 



32
33
34
 
# File 'lib/ltree_hierarchy/hierarchy.rb', line 32

def at_depth(depth)
  where(["nlevel(#{ltree_path_column}) = ?", depth])
end

#has_ltree_hierarchy(options = {}) ⇒ Object 



3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
 
# File 'lib/ltree_hierarchy/hierarchy.rb', line 3

def has_ltree_hierarchy(options = {})
  options = {
    :fragment => :id,
    :parent_fragment => :parent_id,
    :path => :path
  }.merge(options)

  options.assert_valid_keys(:fragment, :parent_fragment, :path)

  cattr_accessor :ltree_fragment_column, :ltree_parent_fragment_column, :ltree_path_column

  self.ltree_fragment_column        = options[:fragment]
  self.ltree_parent_fragment_column = options[:parent_fragment]
  self.ltree_path_column            = options[:path]

  belongs_to :parent, :class_name => self.name, :foreign_key => self.ltree_parent_fragment_column

  validate :prevent_circular_paths, :if => :ltree_parent_fragment_changed?

  after_create  :commit_path
  before_update :assign_path, :cascade_path_change, :if => :ltree_parent_fragment_changed?

  include InstanceMethods
end

#leaves ⇒ Object 



36
37
38
39
 
# File 'lib/ltree_hierarchy/hierarchy.rb', line 36

def leaves
  subquery = select("DISTINCT #{ltree_parent_fragment_column}")
  where("#{ltree_fragment_column} NOT IN(#{subquery.to_sql})")
end

#lowest_common_ancestor_paths(paths) ⇒ Object 



41
42
43
44
45
46
47
48
49
50
 
# File 'lib/ltree_hierarchy/hierarchy.rb', line 41

def lowest_common_ancestor_paths(paths)
  sql = if paths.respond_to?(:to_sql)
    "SELECT lca(array(#{paths.to_sql}))"
  else
    return [] if paths.empty?
    safe_paths = paths.map { |p| "#{connection.quote(p)}::ltree" }
    "SELECT lca(ARRAY[#{safe_paths.join(', ')}])"
  end
  connection.select_values(sql)
end

#lowest_common_ancestors(paths) ⇒ Object 



52
53
54
 
# File 'lib/ltree_hierarchy/hierarchy.rb', line 52

def lowest_common_ancestors(paths)
  where(ltree_path_column => lowest_common_ancestor_paths(paths))
end

#roots ⇒ Object 



28
29
30
 
# File 'lib/ltree_hierarchy/hierarchy.rb', line 28

def roots
  where(self.ltree_parent_fragment_column => nil)
end