所有嵌套后代深嵌套

debugcn 发表于 Dev

阿尼什

我有包含所有父子记录的分类表：

<ActiveRecord::Relation [

#<Spree::Taxon id: 1, parent_id: nil, position: 0, name: "Brands", 
permalink: "brands", taxonomy_id: 1, lft: 1, rgt: 20, 
icon_file_name: nil, icon_content_type: nil, icon_file_size: nil, icon_updated_at: nil, 
description: nil, created_at: "2017-06-14 08:52:19", updated_at: "2017-06-23 06:34:11", 
meta_title: nil, meta_description: nil, meta_keywords: nil, depth: 0>, 

#<Spree::Taxon id: 2, parent_id: nil, position: 0, name: "Brand", permalink: "brand", taxonomy_id: 2, lft: 21, rgt: 22, 
icon_file_name: nil, icon_content_type: nil, icon_file_size: nil, icon_updated_at: nil, description: nil, 
created_at: "2017-06-14 08:52:19", updated_at: "2017- 06-14 08:52:22", meta_title: nil, 
meta_description: nil, meta_keywords: nil, depth: 0>, 

#<Spree::Taxon id: 3, parent_id: 1, position: 0, name: 
"Bags", permalink: "brands/bags", taxonomy_id: 1, lft: 2, rgt: 3, 
icon_file_name: nil, icon_content_type: nil, icon_file_size: nil, 
icon_updated_at: nil, description: nil, created_at: "2017-06-14 
08:52:19", updated_at: "2017-06-21 05:03:52", meta_title: nil, 
meta_description: nil, meta_keywords: nil, depth: 0>, 

#<Spree::Taxon id: 4, parent_id: 1, position: 0, name: "Mugs", permalink: 
"brands/mugs", taxonomy_id: 1, lft: 4, rgt: 5, icon_file_name: nil, 
icon_content_type: nil, icon_file_size: nil, icon_updated_at: nil, 
description: nil, created_at: "2017-06-14 08:52:20", updated_at: "2017-
06-14 08:58:29", meta_title: nil, meta_description: nil, meta_keywords: 
nil, depth: 0>, 

#<Spree::Taxon id: 5, parent_id: 1, position: 0, name: 
"Clothing", permalink: "brands/clothing", taxonomy_id: 1, lft: 6, rgt: 
11, icon_file_name: nil, icon_content_type: nil, icon_file_size: nil, 
icon_updated_at: nil, description: nil, created_at: "2017-06-14 
08:52:20", updated_at: "2017-06-23 06:34:11", meta_title: nil, 
meta_description: nil, meta_keywords: nil, depth: 0>, 

#<Spree::Taxon id: 6, parent_id: 5, position: 0, name: "Shirts", permalink: 
"brands/clothing/shirts", taxonomy_id: 1, lft: 7, rgt: 8, 
icon_file_name: nil, icon_content_type: nil, icon_file_size: nil, 
icon_updated_at: nil, description: nil, created_at: "2017-06-14 
08:52:20", updated_at: "2017-06-20 06:10:16", meta_title: nil, 
meta_description: nil, meta_keywords: nil, depth: 0>, 

#<Spree::Taxon id: 7, parent_id: 5, position: 0, name: "T-Shirts", permalink: 
"brands/clothing/t-shirts", taxonomy_id: 1, lft: 9, rgt: 10, 
icon_file_name: nil, icon_content_type: nil, icon_file_size: nil, 
icon_updated_at: nil, description: nil, created_at: "2017-06-14 
08:52:20", updated_at: "2017-06-23 06:34:11", meta_title: nil, 
meta_description: nil, meta_keywords: nil, depth: 0>, 

#<Spree::Taxon id: 8, parent_id: 1, position: 0, name: "Ruby", permalink: 
"brands/ruby", taxonomy_id: 2, lft: 12, rgt: 13, icon_file_name: nil, 
icon_content_type: nil, icon_file_size: nil, icon_updated_at: nil, 
description: nil, created_at: "2017-06-14 08:52:21", updated_at: "2017-
06-20 06:09:31", meta_title: nil, meta_description: nil, meta_keywords: 
nil, depth: 0>, 

#<Spree::Taxon id: 9, parent_id: 1, position: 0, name: 
"Apache", permalink: "brands/apache", taxonomy_id: 2, lft: 14, rgt: 15, 
icon_file_name: nil, icon_content_type: nil, icon_file_size: nil, 
icon_updated_at: nil, description: nil, created_at: "2017-06-14 
08:52:21", updated_at: "2017-06-23 06:34:11", meta_title: nil, 
meta_description: nil, meta_keywords: nil, depth: 0>, 

#<Spree::Taxon id: 10, parent_id: 1, position: 0, name: "Spree", permalink: 
"brands/spree", taxonomy_id: 2, lft: 16, rgt: 17, icon_file_name: nil, 
icon_content_type: nil, icon_file_size: nil, icon_updated_at: nil, 
description: nil, created_at: "2017-06-14 08:52:21", updated_at: "2017-
06-14 08:58:29", meta_title: nil, meta_description: nil, meta_keywords: 
nil, depth: 0>, ...]>

我需要这样的树结构：

parent1(first taxon(first record) with all child if it has)
  - child1
  - child2
  - child3
    - child7
    - child9
  - child4
  - child5
parent2(it has no child)
parent3(Not it has child)
  - child7
  - child9

我简而言之，我需要每个单独的分类单元及其嵌套的子项。

我尝试过类似的事情：

Taxon.all.each do |i| 
     i.self_and_descendants.each do |j|
       taxon_with_childs << j
     end

但这给出了普通数组，但我想要带有父子嵌套的数组。

我也试过：

Taxon.each_with_level(Taxon.root.self_and_descendants) do |taxon, level|
    taxon_with_childs << taxon
  end

但这只是给第一个记录的孩子，而不是深度嵌套。

用户8214535

我认为它可以通过 DFS 功能完成

def add_self_and_descendents(x, taxon_with_childs)
  taxon_with_childs << x
  x.descendants.each do |y|
    add_self_and_descendents(y, taxon_with_childs)
  end
end

Taxon.all.each do |i| 
  add_self_and_descendents(i, taxon_with_childs)
end

而且如果数据库越来越大，时间会很长。但是没有其他方法可以在短时间内做到这一点，因为数据库操作函数只使用常量值，例如Taxon.where(:parent_id => 1 )

希望这对你有用。

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